Highly precision carbon dioxide acoustic wave sensor with minimized humidity interference

Extensive applications of carbon dioxide (CO2) in various fields, such as food industry, agricultural production, medical and pharmacological industries, have caused a great demand for high-performance CO2 sensors. However, most existing CO2 sensors suffer from poor performance in a wet environment and often cannot work accurately in a high humidity condition. In this study, a quartz crystal resonator (QCR) coated with a uniform layer of reduced graphene oxide (RGO) is proposed to detect both the concentrations of CO2 and water molecules simultaneously, which can be used to significantly minimize the humidity interference. Unlike the other common gas sensors, the RGO-based CO2 QCR sensor can be operated in different humidity levels and the concentration of CO2 can be quantified precisely and effectively. Moreover, it has a fast response (~0.4 s), which is also suitable for respiration monitoring. Our results showed that before and after a volunteer did a low-intensity exercise, the sensor could detect the differences of concentrations of CO2 in the exhaled breath (i.e., 4.50% and 5.15%, respectively)

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

Ferroelectric SnPz/In₂Se₃ as a Stable and Durable Non-Volatile 2D Ferroelectric Memory Material

In ferroelectric memory, the repeated application of external electric fields can cause ferroelectric fatigue, limiting its stability and service life, especially as the storage unit size decreases. To address this issue, we conducted first-principles research on a SnPz/In2Se3 structure and examined its structure under different polarization directions. Our analysis revealed significant differences in the adsorption position of Sn atoms depending on the polarization direction, suggesting that SnPz/In2Se3 could be a highly stable ferroelectric storage material. Moreover, the polarization-induced changes in the electronic structure near the Fermi level, which allowed for the use of tunneling current and obtaining stored information without causing the ferroelectric fatigue effect during information readout. These findings highlight the potential of SnPz/In2Se3 to significantly extend the lifespan of ferroelectric materials, reduce energy consumption, and minimize the environmental impact of discarded electronic devices

Experimental Research on Influencing Factors of High-purity Ferro-Phosphorus and Silicon Thermal Method

In this study, phosphate rock and iron powder were used as raw materials, and industrial silicon is used as a reducing agent. Through orthogonal experiments, the effects of smelting temperature, holding time and silicon ratio on the carbon content, titanium content, phosphorus content and the recovery rate of phosphorus in ferro-phosphorus alloy products are studied. The results show that the carbon content in ferro-phosphorus alloys obtained in the experiment is less than 0.043%, and the titanium content is less than 0.036%. The order of the degree of influence of various factors on the phosphorus content and the recovery rate of phosphorus from large to small is: silicon ratio, smelting temperature, holding time. The best process conditions for preparing ferro-phosphorus alloy by electro-silicothermic process are smelting temperature of 1390 ℃, holding time of 60 min, and silicon ratio of 1.2. Under these conditions, the ferro-phosphorus alloy has a carbon content of 0.010%, a titanium content of 0.036%, and a phosphorus content of 27.78%. The recovery rate of phosphorus was 96.49%

Influence of Temperature on All-Silica Fabry-Pérot Pressure Sensor

An all-silica Fabry-Pérot interferometer (FPI) is demonstrated for high-temperature pressure monitoring. The pressure sensor is fabricated with single mode fiber and silica capillary by CO2 laser. Owing to slight mismatch of thermal expansion coefficient in all-silica structure, it can work stably under 600°C atmosphere. The influence of the temperature on the pressure sensor was investigated within a temperature range from 25°C to 700°C and a pressure range from standard atmosphere pressure to 4 MPa. The experimental results show that the wavelength shift versus the pressure at each temperature is linear, which indicates the proposed FPI pressure sensor has potential applications in industrial reactors, oil and gas wells, and so on

Chalkiness Characters and Scanning Electron Microscope Observation of Rice Grain Endosperm of Japonica Varieties in Southern Henan

Chalkiness characters affect not only the grain appearance, milling, eating and cooking qualities but also the grain nutritional quality in rice, thus it is one of the most important traits in rice. It is very important for us to investigate the relation of the chalkiness formation and the development of endosperm structure and starch granule of different rice varieties. Here, we have investigated the chalkiness characters such as chalkiness rate, chalkiness degree and chalkiness area in 15 japonica rice varieties from southern Henan. Furthermore, the endosperm structure and starch granules of rice grain were also observed with scanning electron microscope. The results showed that the 15 japonica varieties have a significantly linear relationship between the chalkiness rate and chalkiness degree. Among the varieties, the biggest difference is the chalkiness rate, the second is the chalkiness area, and the last is the chalkiness degree. Moreover, there is a certain correlation between the distribution of starch granules, the arrangement of endosperm cells and the occurrence of grain chalkiness in the different rice varieties. For the same variety, the starch granules of chalky and non-chalky grains have obvious difference, while the starch granules from the transparent part of chalky rice and non-chalky rice do not have significant difference. The results would provide useful references for the improvement of grain quality in rice

Clinical evidence for acupuncture for adult asthma: Systematic review and meta-analysis of randomised sham/placebo-controlled trials

Objective: Acupuncture is a widely used asthma therapy, but the benefits remain uncertain. This study aimed to access the effectiveness of acupuncture for treatment of asthma in adults. Methods: Five English databases and four Chinese databases were searched from inception to November 2021. Randomised sham/placebo-controlled trials meeting inclusion criteria were included. Risk of bias was evaluated according to the Cochrane Review Handbook, and data analysis was performed in RevMan 5.4.1. Quality of evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluations (GRADE) profiler. Results: Sixteen randomised controlled trials (RCTs) were included in the meta-analysis. Results indicated that acupuncture was well-tolerated and could improve FEV1% compared with sham/placebo acupuncture [MD 6.11, 95% CI 0.54–11.68, I2 = 93%, number of participants (n) = 603]. Acupuncture also improved Cai’s Asthma Quality of Life Questionnaire (AQLQ) (MD 7.26, 95% CI 5.02–9.50, I2 = 0, n = 358), and reduced the asthma symptom score (SMD −2.73, 95% CI −3.59 to −1.87, I2 = 65%, n = 120). One study showed acupuncture increased the Asthma Control Test (ACT) score (MD 2.00, 95% CI 0.90–3.10, n = 111), and decreased exacerbation frequency (MD −1.00, 95% CI −1.55 to −1.45, n = 111). Other lung function and medication use parameters were not statistically significant. Conclusions: Acupuncture versus sham/placebo control appeared to improve quality of life, FEV1%, symptoms, and asthma control, and reduced exacerbation frequency per year. Further studies with appropriate controls, more participants, and high-quality evidence are needed