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The different shapes and sizes of wine glass are claimed to balance the different wine aromas in the headspace, enhancing the olfactory perception and providing an adequate level of oxygenation. Although the measurement of dissolved oxygen in winemaking has recently received much focus, the role of oxygen in wine tasting needs to be further disclosed. This preliminary study aims to explore, for the first time, the effect of swirling glasses of different shapes and sizes on the oxygen content of wine. Experimental trials were designed to simulate real wine tasting conditions. The O2 content after glass swirling was affected to a considerable extent by both the type of wine and the glass shape. A lack of correlation between the shape parameters of five glasses and the O2 content in wine was found which suggests that the nonequilibrium condition can occur during wine tasting. The International Standard Organisation (ISO) glass--considered to be optimal for the wine tasting--allowed less wine oxygenation than any other glass shapes; and the apparent superiority of the ISO glass is tentatively attributed to the more stable oxygen content with time; i.e., less variability in oxygen content than any other glass shape. [ABSTRACT FROM AUTHOR]

With research and development for almost one century, the Taylor-Couette device is now applied in many practical applications such as reaction, filtration, extraction and bioreactor. We intend to use the Taylor-Couette bioreactor to culture cells that are seeded in a biodegradable porous scaffold. Oxygen concentration is always the most significant constraint in a bioreactor and can limit the cell proliferation rate. It is therefore important to know the mass transfer phenomenon and oxygen transport pattern inside the system. In this study, the equilibrium oxygen concentrations at different Reynolds numbers and operation conditions were measured and the mass transfer coefficients were also calculated. CFD simulation was carried out to compare with the experimental results. Both experimental and simulation results showed that the equilibrium oxygen concentration and mass transfer coefficient increased with Reynolds number. To further improve the mass transfer efficiency, air bubble was introduced to the bottom of the rotating inner cylinder and the vortex center. It was shown that the mass transfer coefficient of oxygen could be significantly increased with the trapped bubble. [ABSTRACT FROM AUTHOR]

This paper discusses the dynamics of oxygen partial pressure in intercellular fluid upon a limited load and a subsequent post-ischemic hyperemia in healthy individuals and individuals with vascular pathologies of the lower limbs. Within the framework of the phenomenological approach, which takes into consideration the qualitative peculiarities of the gas exchange processes in the body, a formal theory describing the dynamics of oxygen () concentration dependently on the conditions of blood supply to the tissues has been developed. It was shown that certain parameters, for instance the relaxation time upon the conditions of artificial ischemia and the characteristic time of return of spontaneous blood circulation in the post-ischemic period, depend on the degree of pathology of the vascular system and may be used for assessing the functional status of a biological body. [ABSTRACT FROM AUTHOR]

In this study, dual luminescent polymer sensors based on a pressure-sensitive palladium(II) tetraphenylporphyrin, PdTPP, and a temperature-sensitive europium(III) complex, EuDT, were newly fabricated by spray-coating or electrospinning of the solutions containing polystyrene as a matrix for the simultaneous detection of both pressure and temperature. The pressure and temperature responses were recorded as a function of the luminescence changes, and their sensitivities were carefully evaluated. The electrospun nanofibrous films exhibited a higher pressure-sensitivity than the corresponding spray-coated films, which was most likely attributed to their highly porous structures. In addition, accurate temperatures at the sample surface were determined from the luminescence intensities of the temperature-sensitive dye, which were used for the temperature correction of the surface pressure measurements. It was demonstrated that the accuracy of the pressure measurements based on the luminescence intensities of the pressure-sensitive dye was significantly improved after the temperature corrections. This is the first report of dual luminescent nanofibrous polymer sensors. [ABSTRACT FROM AUTHOR]

Notwithstanding these caveats, Kim et al.,'s data are consistent with previous findings that obesity-induced carotid body leptin resistance is not because of saturation of the leptin receptor signalling caused by excess circulating leptin. However, enhanced baseline ventilation with Trpm7 knockdown suggests that normally carotid body TRPM7 is active in obesity despite leptin resistance, and contributes to obesity-associated ventilatory I suppression i . Keywords: breathing; carotid body; leptin; lysophosphatidic acid; metabolic syndrome; obesity; oxygen sensor; TRP channels; TRPM7; TRPV1; venous chemoreceptor EN breathing carotid body leptin lysophosphatidic acid metabolic syndrome obesity oxygen sensor TRP channels TRPM7 TRPV1 venous chemoreceptor 4965 4966 2 12/02/22 20221201 NES 221201 In their traditional orbit, the carotid bodies are the preeminent peripheral arterial blood gas sensors, regulating ventilation and autonomic activity. [Extracted from the article]

Lignin preparations from kraft and sulfite pulping, steam explosion, and enzyme saccharification processes were assessed as substrates for lignin polymerization catalyzed by Trametes hirsuta laccase (ThL). Oxygen consumption associated with laccase catalyzed oxidation of the selected lignins was measured using a microplate-based oxygen assay. Laccase-induced changes in the molecular masses of the lignin polymers were assessed with aqueous-alkaline size exclusion chromatography (SEC) and changes in monomeric phenolics by reverse-phase high pressure liquid chromatography (HPLC). Obtaining consistent results in the lignin-laccase assay system required careful pH monitoring and control. All lignin preparations were oxidized by ThL, the rate being highest for steam-exploded eucalypt and lowest for enzyme-saccharified lignin. Comparing lignins, higher lignin-laccase reactivity was correlated with lower lignin molecular mass and higher amounts of monomeric phenolics. Solubility was not an indicator of reactivity. Steam-exploded and lignosulfonate-treated pine preparations were further fractionated by ultrafiltration to determine what molecular mass fractions were the most reactive in ThL catalyzed oxidation. Both retentate (> 3kDa), and to a lesser degree permeate (< 3kDa), fractions were reactive.

A chromatic sensor has been designed for the detection of oxygen in package headspace. The sensor is based on the redox change of methylene blue (MB) to its leuco form. Its formulation includes the pigment, glycerol, as a sacrificial electron donor, TiO2, as a photocatalyst and ethylene-vinyl alcohol copolymer (EVOH), as a structural polymer matrix. The final sensor design that allows its manufacture by conventional printing and laminating technologies consists of the sensing polymer matrix (MB-EVOH) sandwiched in a suitable transparent multilayer structure. The outer layers protect the sensor from the external atmosphere and allow visualization of the colour. The inner layer is sufficiently opaque to facilitate sensor reading from the outside, is thick enough to avoid direct contact with food (functional barrier), and is oxygen-permeable to expose the sensing material to the internal package atmosphere. In the absence of oxygen, the sensor becomes white by irradiation with halogen lamps in less than 60 s. All components are substances permitted for food contact except the pigment, but specific migration analysis showed no trace of migration thanks to the functional barrier included in the design.

Luminescence-based sensors for measuring oxygen concentration are widely used in both industry and research due to the practical advantages and sensitivity of this type of sensing. The measuring principle is the luminescence quenching by oxygen molecules, which results in a change of the luminescence decay time and intensity. In the classical approach, this change is related to an oxygen concentration using the Stern-Volmer equation. This equation, which in most cases is non-linear, is parameterized through device-specific constants. Therefore, to determine these parameters, every sensor needs to be precisely calibrated at one or more known concentrations. This study explored an entirely new artificial intelligence approach and demonstrated the feasibility of oxygen sensing through machine learning. The specifically developed neural network learns very efficiently to relate the input quantities to the oxygen concentration. The results show a mean deviation of the predicted from the measured concentration of 0.5% air, comparable to many commercial and low-cost sensors. Since the network was trained using synthetically generated data, the accuracy of the model predictions is limited by the ability of the generated data to describe the measured data, opening up future possibilities for significant improvement by using a large number of experimental measurements for training. The approach described in this work demonstrates the applicability of artificial intelligence to sensing technology and paves the road for the next generation of sensors.

In this paper, a highly monolithic-integrated multi-modality sensor is proposed for intracorporeal monitoring. The single-chip sensor consists of a solid-state based temperature sensor, a capacitive based pressure sensor, and an electrochemical oxygen sensor with their respective interface application-specific integrated circuits (ASICs). The solid-state-based temperature sensor and the interface ASICs were first designed and fabricated based on a 0.18-μm 1.8-V CMOS (complementary metal-oxide-semiconductor) process. The oxygen sensor and pressure sensor were fabricated by the standard CMOS process and subsequent CMOS-compatible MEMS (micro-electromechanical systems) post-processing. The multi-sensor single chip was completely sealed by the nafion, parylene, and PDMS (polydimethylsiloxane) layers for biocompatibility study. The size of the compact sensor chip is only 3.65 mm × 1.65 mm × 0.72 mm. The functionality, stability, and sensitivity of the multi-functional sensor was tested ex vivo. Cytotoxicity assessment was performed to verify that the bio-compatibility of the device is conforming to the ISO 10993-5:2009 standards. The measured sensitivities of the sensors for the temperature, pressure, and oxygen concentration are 10.2 mV/◦C, 5.58 mV/kPa, and 20 mV.L/mg, respectively. The measurement results show that the proposed multi-sensor single chip is suitable to sense the temperature, pressure, and oxygen concentration of human tissues for intracorporeal physiological condition monitoring. [ABSTRACT FROM AUTHOR]

An indirect way of assessing cadmium concentration in confined volume was attempted. This aim was met by measuring the oxygen concentration before and after reaction with cadmium vapour. The deduced cadmium concentration value corroborated with the data obtained from cadmium vapour pressure at different temperature. [ABSTRACT FROM AUTHOR]

In recent years, room temperature ionic liquids (RTILs) have been highly utilized in electrochemical fields. Specifically, ionic liquids (ILs) as electrolytes augur promising potential for the next generation of advanced and miniaturized electrochemical gas sensors. In this paper, 1-ethyl-3-methylimidazolium hexafluorophosphate ([EMIM][PF 6 ]), 1-propyl-3-methylimidazolium hexafluorophosphate ([PMIM][PF 6 ]) and 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF 6 ]) were synthesized through a facile one-pot method. We found that [EMIM][PF 6 ] and [PMIM][PF 6 ] exist in the solid state at room temperature. Hence, these ILs can effectively avoid the leakage of electrolytes. However, [BMIM][PF 6 ] can be present in liquid state at room temperature as the melting point decreases, due to the increasing of alkyl chain (C n , n < 6) for the ILs. Compared to solid electrolyte gas sensors, sensors based on liquid electrolytes offer a reliable response and achieve sufficient ion mobility to sense oxygen. Our work provides an incentive to enhance the properties of a liquid electrolyte by mixing it with Pt-modified ordered mesoporous carbons (Pt-OMCs), which not only prevents the aggregation of OMCs but also provides a large number of active sites for oxygen reduction. The limit of detection (LOD) in oxygen sensors based on Pt/CMK-3-COOH-[BMIM][PF 6 ] is relatively low (1.10% O 2 ). Our results indicate that the synergistic combination of ILs and Pt-OMCs markedly promotes the performance of electrochemical oxygen sensors. [ABSTRACT FROM AUTHOR]

Hypoxic pulmonary vasoconstriction (HPV) is a physiological reaction, which adapts lung perfusion to regional ventilation and optimizes gas exchange. Impaired HPV may cause systemic hypoxemia, while generalized HPV contributes to the development of pulmonary hypertension. The triggering mechanisms underlying HPV are still not fully elucidated. Several hypotheses are currently under debate, including a possible decrease as well as an increase in reactive oxygen species as a triggering event. Recent findings suggest an increase in the production of reactive oxygen species in pulmonary artery smooth muscle cells by complex III of the mitochondrial electron transport chain and occurrence of oxygen sensing at complex IV. Other essential components are voltage-dependent potassium and possibly L-type, transient receptor potential channel 6, and transient receptor potential vanilloid 4 channels. The release of arachidonic acid metabolites appears also to be involved in HPV regulation. Further investigation of the HPV mechanisms will facilitate the development of novel therapeutic strategies for the treatment of HPV-related disorders. [ABSTRACT FROM AUTHOR]

Mycobacterium tuberculosis strongly relies on a latency, or nonreplicating persistence, to escape a human host's immune system. The DevR (DosR), DevS (DosS), and DosT proteins are key components of this process. Like the rhizobial FixL oxygen sensor, DevS and DosT are histidine protein kinases with a heme-binding domain. Like the FixJ partner and substrate of FixL, DevR is a classical response regulator of the two-component class. When activated by DevS or DosT during hypoxia in vivo, DevR induces a dormancy regulon of more than 40 genes. To investigate the contributions of DevS, DosT, and target DNA to the phosphorylation of DevR, we developed an in vitro assay in which the full-length, sensing, DevS and DosT proteins were used to phosphorylate DevR with ATP, in the presence of target DNAs that were introduced as oligonucleotides linked to magnetic nanoparticles. We found that the DevR phosphorylations proceeded only for the deoxy states of the sensors. The reaction was strongly inhibited by O2, but not CO or NO. The production of phospho-DevR was enhanced sixfold by target consensus DNA or acr- DNA. The phospho-DevR bound tightly to that DNA ( Kd ~ 0.8 n m toward acr- DNA), and it was only slightly displaced by a 200-fold excess of unphosphorylated DevR or of a truncated DevR with only a DNA-binding domain. To our knowledge, this represents the first in vitro study of the ligand regulation of DevR phosphorylation by full-length DevS and DosT, and demonstration of a positive effect of DNA on this reaction. [ABSTRACT FROM AUTHOR]

In this work, we presented a facile and cost-effective approach to fabricate novel PtTFPP/PDMS micro-pillar array (MPA) sensor film with I 0 /I 100 for gaseous oxygen and dissolved oxygen are 288 and 84, respectively. The sensitivity of the sensor film exhibited over ∼30-fold increment when compared with contemporary PtTFPP/PDMS-based oxygen sensors. The detection limit was as low as 0.10 μmol/L, which means that the ultrasensitive sensor films enable reliable monitoring of dissolved oxygen (DO) within nanomolar concentration ranges that are particularly difficult to achieve in previous works. Furthermore, the remarkably light intensity-changing characteristic of the sensing film under lower O 2 partial pressures facilitates convenient identification of O 2 concentrations even with the naked eye. We believe that the proposed device could be a promising candidate in various oxygen sensing fields such as nearly anoxic systems, unsteady pressure measurement and unsteady flow visualization, etc. [ABSTRACT FROM AUTHOR]

The present investigation has been carried out to optimize the pH level of lanthanum (La)-doped tin dioxide (SnO) nanoparticles towards the potential application in gas sensor. The La-doped SnO nanoparticles were synthesized by sol-gel method in different pH values varying from acidic to base nature. The synthesized nanoparticles were characterized by X-ray diffraction (XRD), ultraviolet (UV), photoluminescence (PL), and scanning electron microscopy (SEM) techniques. The XRD, UV, and PL analyses show the pH influences on the crystallite size of La-doped SnO nanoparticles. The SEM images show the formation of porous structure at pH 11. Also, the electrical conductivity of 1 mol% La-doped SnO at pH 3 and pH 11 were measured by impedance analyzer. In addition, we have fabricated and demonstrated device performance of synthesized La-doped SnO nanoparticles for gas-sensing application. Real-time current response and long-time response to the gas sensing were also studied for the fabricated device. [ABSTRACT FROM AUTHOR]

The incorporation of 1-alkyl-3-methylimidazolium hexafluorophosphate (AMIMPF 6 ) and 1-vinlyimidazole (VIM) firstly served as electrolyte for oxygen sensor, which remarkably promoted response current. Moreover, the sheet-like structure of cobalt was deposited onto the surface of C@TiC nanowire (Co/C), which endowed the imidazole-based ionic liquid electrolyte with plentiful active sites and fast electron transfer rate for oxygen reduction reaction. There was little literature about the integration of AMIMPF 6 , VIM and Co/C as the electrolyte for oxygen sensor. The synergistic effect among all components was realized and maximized, leading to a superior performance of oxygen sensing compared to any component alone. The most important was that the composite material showed a fast response towards oxygen with an excellent linear relationship. [ABSTRACT FROM AUTHOR]

A systematic structure-photoproperties relationship study of the interactions of porphyrin-fullerene dyads with molecular oxygen was conducted on a set of three porphyrin-fullerene dyads, as this approach of related applications - oxygen sensitivity and photo-induced singlet oxygen generation - of such dyads remained to be endeavoured. To promote energy transfers between the porphyrin and fullerene units and limit undesired charge separation, a particular attention was devoted to the choice of the solvents for the photoproperties determination. Toluene, in which in addition the compounds investigated are not aggregated, was selected accordingly. The molecular orbital levels and energy gaps of the dyads were determined by electrochemistry and theoretical calculations. Their ground state absorption, steady-state fluorescence-based oxygen sensitivity and photo-induced singlet oxygen generation were determined. The dyads were designed to benefit from a facilitated synthetic porphyrin-fullerene coupling thanks to an easy access to formyl-functionalized porphyrins. The effect of two structural parameters was investigated: the presence of electron-donating hexyloxy chains at the para position of the meso-phenyl, and the presence of a phenylacetylene spacer. This latest factor appeared to have the most predominant effect on all these properties. [ABSTRACT FROM AUTHOR]

Sulfur-containing additives are still widely found in fuel oil, especially in the developing countries. Sulfur is considered to have a negative impact on the electrocatalytic activity of Pt and Ni. In this work, pure TiO 2 and Pt/TiO 2 based lambda oxygen sensors were prepared and treated with sulfur, respectively. The gas response properties of the sensors indicated that the sulfur had adverse effects on Pt/TiO 2 gas sensor, but not on the pure TiO 2 sensor. The surface states of O, Pt and S present on the sensing film surface were studied by XPS in depth. The valence-state of Pt on the Pt/TiO 2 sensor was proposed to be PtSO 4 , indicating that the catalytic activity of Pt was severely weakened by sulfur. [ABSTRACT FROM AUTHOR]

A graft copolymer composed of poly( ε -caprolactone) as a hydrophobic chain and poly( N -(2-hydroxypropyl)methacrylamide) as a hydrophilic segment with an internal reference probe for oxygen sensing was prepared. Highly efficient platinum(II)meso-tetra(pentafluorophenyl)porphine (PtTFPP) was used as a typical oxygen probe. Although PtTFPP was highly efficient, it is hydrophobic, limiting its direct application for oxygen sensing in biological conditions. By using the amphiphilic graft copolymer, PTTFPP was successfully incorporated into the micelles formed by this polymer to not only enable the application of PtTFPP for biosensing in medium but also retain its high efficiency. The quantum efficiency of PtTFPP in the micelle solution under nitrogen can reach as high as 0.20. The PtTFPP-containing micelles were tested for high throughput cell respiration and bacteria detection. The influence of an antibiotic, antimycin as a representative example, on cell respiration was also studied. For achieving high accurate sensing, an internal built-in reference probe with aggregation induced emission properties were also polymerized in the graft copolymer. This study demonstrated that the graft polymer approach is a good way to enable highly efficient and hydrophobic oxygen probes for biosensing. [ABSTRACT FROM AUTHOR]

Stereo Particle Image Velocimetry (SPIV) is used to measure the highly turbulent flow in the upstream region of the catalytic converter for a four stroke IC engine. These experiments are conducted for a motorized engine to investigate the feasibility of using SPIV for exhaust flow measurements in a firing IC engine in our future research. The results obtained here can also be used for validation of the CFD models. The measured flow is highly three dimensional, non-uniform with large magnitudes of turbulence indicating recirculating flow structures. These structures show signatures of jet flows coming out of the exhaust valves at all exhaust crank angles. The triangular shape and location for the end face of each exhaust runner pipe, the length and geometry of the runners also affect the flow mixing process upstream of the catalytic converter contributing to the complexity of this flow. Although majority of the exhaust flow passes through the catalytic converter, some will recirculate due to impingement of the exhaust jets on the surface of the catalyst. [ABSTRACT FROM AUTHOR]

FixL from Rhizobium etli (ReFixL) is a hybrid oxygen sensor protein. Signal transduction in Re FixL is effected by a switch off of the kinase activity on binding of an oxygen molecule to ferrous heme iron in another domain. Cyanide can also inhibit the kinase activity upon binding to the heme iron in the ferric state. The unfolding by urea of the purified full-length ReFixL in both active pentacoordinate form, met-FixL(Fe III ) and inactive cyanomet-FixL (Fe III -CN − ) form was monitored by UV–visible absorption spectroscopy, circular dichroism (CD) and fluorescence spectroscopy. The CD and UV–visible absorption spectroscopy revealed two states during unfolding, whereas fluorescence spectroscopy identified a three-state unfolding mechanism. The unfolding mechanism was not altered for the active compared to the inactive state; however, differences in the ΔG H2O were observed. According to the CD results, compared to cyanomet-FixL, met-FixL was more stable towards chemical denaturation by urea (7.2 vs 4.8 kJ mol − 1 ). By contrast, electronic spectroscopy monitoring of the Soret band showed cyanomet-FixL to be more stable than met-FixL (18.5 versus 36.2 kJ mol − 1 ). For the three-state mechanism exhibited by fluorescence, the ΔG H2O for both denaturation steps were higher for the active-state met-FixL than for cyanomet-FixL. The overall stability of met-FixL is higher in comparison to cyanomet-FixL suggesting a more compact protein in the active form. Nonetheless, hydrogen bonding by bound cyanide in the inactive state promotes the stability of the heme domain. This work supports a model of signal transduction by FixL that is likely shared by other heme-based sensors. [ABSTRACT FROM AUTHOR]

The discovery of the globin-coupled sensor (GCS) family of haem proteins has provided new insights into signalling proteins and pathways by which organisms sense and respond to changing oxygen levels. GCS proteins consist of a sensor globin domain linked to a variety of output domains, suggesting roles in controlling numerous cellular pathways, and behaviours in response to changing oxygen concentration. Members of this family of proteins have been identified in the genomes of numerous organisms and characterization of GCS with output domains, including methyl accepting chemotaxis proteins, kinases, and diguanylate cyclases, have yielded an understanding of the mechanism by which oxygen controls activity of GCS protein output domains, as well as downstream proteins and pathways regulated by GCS signalling. Future studies will expand our understanding of these proteins both in vitro and in vivo, likely demonstrating broad roles for GCS in controlling oxygen-dependent microbial physiology and phenotypes. [ABSTRACT FROM AUTHOR]