Investigation into the thermal comfort and physiological adaptability of outdoor physical training in college students.

Over the last few decades, increase in global temperatures have led to a deterioration in the quality of open spaces, urban vitality, and public health. Strenuous physical training under hot conditions outdoors increases the potential for developing heat illnesses. It is therefore necessary to examine the relationships between human physiological indices, psychological responses, and outdoor thermal indices to predict and evaluate human thermal safety in hot environments. A 9-day experiment was conducted in September 2019, which tested the thermal comfort and cognitive ability of 1102 students. Their physiological parameters (Heart rate, Auditory canal temperature) were recorded before and after physical training. Results showed that there were significant differences in the thermal sensation vote before and after physical training. The classification of heat stress was modified based on the MTSV regression model and PET. The maximum acceptable PET was 23.0 °C before physical training and 21.7 °C after physical training. When PET ≥ 40.1 °C, a reduction in physical training intensity is recommended. When PET ≥ 45.7 °C, cessation of physical training should take place and sun exposure should be reduced to avoid health hazards. It is important to use the auditory canal temperature instead of the core temperature to calculate the physiological strain index (PSI). More than 15% of the subjects had a PSI ≥ 7.0 during the test. When the body is in a thermally neutral state (MTSV = -0.5- 0.5), PSI ≤ 2.0. When the MTSV ≥3.2, PSI ≥ 7.0, physical training intensity should be reduced, and warning information should be provided. According to the expected distribution of physical training time and rest time, it is recommended that the time of each physical training session should be within 30 min, with a resting period of more than 30 min in hot environments.

Au@Carbon quantum Dots-MXene nanocomposite as an electrochemical sensor for sensitive detection of nitrite.

A highly sensitive electrochemical sensor was developed through a one-pot green synthesis method for nitrite detection based on the electrochemical technique. Xylan-based carbon quantum dots (CQDs) were used as green in situ reducing agent to prepare CQDs capped gold nanoparticles (Au@CQDs). MXene of good electrical conductivity was used as the immobilized matrix to fabricate Au@CQDs-MXene nanocomposites with the advantages of good electrical conductivity and electrocatalysis. An electrochemical sensor for nitrite monitor was obtained by loading the Au@CQDs-MXene on a glassy carbon electrode. The sensor presents high sensitivity, good stability, wide linear range, and excellent selectivity due to the high catalytic activity of AuNPs and CQDs, the large specific surface area of MXene, and exceptional electrical conductivity of AuNPs and MXene. Under the optimal condition, the linear detection range of the sensor was from 1 µM to 3200 µM with a detection limit of 0.078 µM (S/N = 3), which was superior to most reported sensors using differential pulse voltammetry (DPV) method. Furthermore, this sensor was successfully applied to detect nitrite in tap water and salted vegetables with satisfactory recoveries. This modified electrocatalytic sensor shows a new pathway to fabricate nitrite detection sensor with feasibility for practical application.

Investigation into outdoor thermal comfort conditions by different seasonal field surveys in China, Guangzhou.

Outdoor microclimatic conditions strongly affect the thermal comfort of pedestrians. A transversal field survey was conducted in Guangzhou, together with micrometeorological measurements. The outdoor physiological equivalent temperature (PET) varied from 3 to 59 °C. Regression lines were obtained to establish correlations of the mean thermal sensation vote (MTSV) with the PET bins with a width of 1 °C. Furthermore, the thermal comfort range of PET, neutral PET (NPET), and preferred PET was analyzed. The results indicated that, for the young people, thermal comfort range of PET spanned from 19.2 to 24.6 °C. The NPET and preferred PET significantly differed in different seasons. The NPET was higher in the summer than that in the winter and transitional seasons. However, the preferred PET of the summer was lower than that of the winter. The PET limits of different thermal stress categories were also confirmed, which differed from those in other cities. Thus, the impacts of adaptation on thermal comfort range were significant for people in outdoor environment.

Process optimization of Syringa oblata Lindl. by response surface methodology and its effect on Staphylococcus xylosus biofilm.

Syringa oblata Lindl. (S. oblata) is a medicinal plant with effective broad-spectrum antibacterial activity, which can also inhibit Streptococcus suis biofilm formation. The processing of herbal medicine can purify medicinal materials, provide acceptable taste, reduce toxicity, enhance efficacy, influence performance and facilitate preparation. Thus, the aim of this study was to enhance the biofilm inhibition activity of S. oblata toward Staphylococcus xylosus (S. xylosus) using the best processing method. The content of rutin and flavonoids and the ability to inhibit the biofilm formation by S. oblata were examined using four processing methods. One of the best methods, the process of stir-frying S. oblata with vinegar, was optimized based on the best rutin content by response surface methodology. The histidine content and hisB gene expression of S. xylosus biofilm in vitro, resulting from stir-frying S. oblata with vinegar, were evaluated and were found to be significantly decreased and down-regulated, respectively. The results show that S. oblata stir-fried with vinegar can be used to effectively treat diseases resulting from S. xylosus infection. This is because it significantly inhibited S. xylosus biofilm formation by interfering with the biosynthesis of histidine; thus, its mechanism of action is decreasing histidine synthesis.