On the thirty-fifth anniversary of the first description of O2-sensitive K+ channels in the carotid body chemoreceptors [1], O2 sensing remains a salient issue in the literature. Whereas much has been learned about this subject, important questions such as the identity of the specific K+ channel subtype(s) responsible for O2 sensing by chemoreceptors and the mechanism(s) by which their activities are altered by hypoxia have not yet been definitively answered. O2 sensing is a fundamental biological process necessary for the acute and chronic responses to varying environmental O2 levels which allow organisms to adapt to hypoxia. Whereas chronic responses depend on the modulation of hypoxia-inducible transcription factors which determine the expression of numerous genes encoding enzymes, transporters and growth factors, acute responses rely mainly on the dynamic modulation of ion channels by hypoxia, causing adaptive changes in cell excitability, contractility, and secretory activity in specialized tissues. The most widely studied oxygen-sensitive ion channels are potassium channels but oxygen sensing by members of both the calcium and sodium channel families has also been demonstrated. Given the explosion of information on this topic, in this review we will focus on the mechanisms of physiological oxygen chemotransduction by PO2-dependent K+ channels, with particular emphasis on their function in carotid body chemoreceptor cells (CBCC) and pulmonary artery smooth muscle cells (PASMC), highlighting areas of consensus and controversy within the field. We will first describe the most well-established concepts, those reproduced in multiple laboratories, and then discuss selected observations or questions that remain unresolved, and that limit our progress in this field.

Several epidemiological studies and intervention trials have demonstrated that flavanols present in grapes and blueberries can lower the risk of cardiovascular disease. However, the mechanisms of action of these compounds remain unclear due to their low bioavailability. A polyphenol-rich grape and blueberry extract (PEGB) contained about 16% flavanol, of which 11% was monomer and 4% was dimer. A sensory test investigated the oral perception of a PEGB. At concentrations where quercetin had almost no detectable taste, PEGB exhibited significant astringency. Furthermore, in comparing the redox properties against O2･- using a luminescence method, PEGB acted as a prooxidant at low concentrations, promoting O2･-production and scavenging O2･-at high concentrations under pH conditions similar to oral cavity and intestine. In contrast, quercetin showed antioxidant activity at any concentration. A single oral administration of PEGB to rats showed a significant increase in skeletal muscle arteriolar blood flow. According to these results, PEGB containing flavanols displays a potent astringent flavor, increases O2･-production at low concentrations in a neutral pH environment as well as oral and intestine, and considerably enhances blood flow to skeletal muscles after a single dose in rats. The results of this study indicate a need to investigate the causal relationship between oral perception, redox properties, and bioactivity of polyphenols.

Using co-precipitation to synthesize (CeO2)0.95(Y2O3)0.05 (YDC) and solid reaction method to synthesize (CeO2)0.75(ZrO2)0.25 (ZDC), and the characterization for both crystal structure and micro-structure of the two materials was conducted with X-ray diffraction (XRD) and scanning electron microscope (SEM) methods. Prepare the YDC and ZDC based limited current O2 sensor by employing platinum pasting bonding method. Sensing characteristics of the sensor were obtained at different conditions and study on the impact of temperature, O2 concentration as well as water vapor pressure on the sensing characteristics had been conducted. XRD results show that the phase structure of both YDC and ZDC is cubic phase. SEM results show that both YDC and ZDC layers are dense layers, which are then qualified to be the composition materials of the sensor. This limited current O2 sensor shows good sensing performance and conforms to the Knudsen model. Log(IL•T) depends linearly on 1000/T with R2 of 0.9904, IL depends linearly on x(O2) with R2 of 0.9726 and sensing characteristics are not affected by p(H2O).

A Pediatric Sleep Questionnaire (PSQ) and a recording of the respiratory parameters with a noc-turnal home cardiorespiratory polygraphy (PG) are necessary to diagnose OSAS. Few researchers have studied how obesity could influence the respiratory parameters in OSAS children. The aim of the study was to investigate how obesity can influence sleep respiratory parameters in OSAS children. Methods: The study analyzes 56 Caucasian children and adolescents aged 11 ± 2.79 years with a BMI> 5th percentiles and PSQ value of 0.33. Children were divided into the Obesity Group (OG) with a BMI of  95th and the Control Group (CG) with a 5th<BMI> 95th percentile. All selected children underwent PG. Respiratory parameters were extracted to divide into levels of severity OSAS: snoring, mild, moderate, and severe. Results: The comparison analysis of AHI, SaO2, and Nadir between the OG and CG showed a statistical significance only for ODI (p = 0.02). The comparison analysis of PSQ between the OG and CG and of PSQ and respiratory parameters showed no significant result. A statistically significant correlation between BMI and AHI (r2=0.01), SaO2 (r2=0.09), and Nadir O2 (r2=0.00) was found. Conclusion: There was no strong correlation between Obesity and OSAS, but it was found between BMI increasing and AHI severity

We report a preliminary exploration on the low-pressure Ar-O2 plasma generated by low-frequency alternating current (AC) power supply in the low-temperature Plasma Experimental Power Supply (CTP-2000S) for the first time. The electron density 〖(n〗_e), the electron temperature 〖(T〗_e) and the electron energy distribution function (EEDF) are measured by the single Langmuir probe in this experiment. Experimental results show that the ne increases with gas pressure rising, while the ne decreases with the oxygen concentrations rising. And, a plasma density peak is also observed with the AC power supply increase. A comparison between this work and the previous results by RF source suggests that the low-frequency AC power supply may be very fruitful exploration to generate the low-pressure plasma.