BackgroundIn recent years, high flow nasal oxygen(HFNO) has been widely used in clinic, especially in perioperative period.Many studies have discussed the role of HFNO in pre- and apneic oxygenation, but their results are controversial.Our study aimed to examine the effectiveness of HFNO in pre- and apneic oxygenation by a meta-analysis ofRCTs.MethodsEMBASE, PUBMED, and COCHRANE LIBRARY databases were searched from inception to July 2021 for relevantrandomized controlled trails(RCTs) on the effectiveness of HFNO versus standard facemask ventilation(FMV) inpre- and apenic oxygenation. Studies involving one of the following six indicators: (1)Arterial oxygen partialpressure(PaO2), (2)End expiratory oxygen concentration(EtO2), (3)Safe apnoea time, (4)Minimum pulse oxygensaturation(SpO2min), (5)Oxygenation(O2) desaturation, (6)End expiratory carbon dioxide(EtCO2) or Arterial carbondioxide partial pressure(PaCO2) were included. We select random effect model or fixed effect model for analysisaccording to the heterogeneity of the article, and express it as the mean difference(MD) or risk ratio(RR) with aconfidence interval of 95%(95%CI). We conducted a risk assessment of bias for eligible studies and assessed theoverall quality of evidence for each outcome.Results14 RCTs and 1012 participants were finally included. We found the PaO2 was higher in HFNO group than FMVgroup with a MD(95% CI) of 57.38 mmHg(25.65 to 89.10; p=0.0004) after preoxygenation and the safe apnoeatime was significantly longer with a MD(95% CI) of 86.93 seconds(44.35 to 129.51; p<0.0001) during anesthesiainduction. There were no significant statistical difference in the minimum O2 saturation, CO2 accumulation, endexpiratory oxygen concentration and O2 desaturation rate during anesthesia induction between the two groups.ConclusionsThis systematic review and meta-analysis suggests that HFNO should be considered as an airway managementtool for patients with high-risk hypoxemia or difficult airway during anesthesia induction. Compared with FMV,continuous use of HFNO during anesthesia induction can significantly improve oxygenation and prolong safeapnoea time in surgical patients.

This paper concerns with two brominated bacteriostatic agents, using the condition-test to research the inhibitory effect of the microorganisms in the waste paper pulp white water. Using the coated plate culture method of adding different amounts of antibacterial agents in Whitewater, the bacteria and mold in nutrient agar and potato medium experiments were used to observe the inhibitory effect. The results showed that the chosen brominated bacteriostatic agents (PS-2890, GB-3612) in this paper have a better antibacterial effect and 1#is better than 2#,the bacteriostatic agent can be chosen according to the actual situation of the plant .The bacteriostatic agent will achieve a higher rate of bacteriostasis when it is added to 5ppm, and this added amount can also meet the requirements of the factory on the prevention and treatment of microbial. The rate of bacteriostasis generally reached 40% -80% ,the highest 92.8%,when the antibacterial dosage is 3ppm-7ppm.

Before oxygen bleaching and hydrogen peroxide bleaching, wheat straw pulp was bleached using xylanase. The effect of enzymatic stage on pulp properties and bleachability has been studied and compared with reference (control) pulps, processed without enzyme addition. Experimental results showed that, the optimal concentration of wheat straw pulp was 10%, the optimal treatment time and dose of enzyme was 60 min and 1.25AXU/g respectively. Oxygen pressure decreased from 0.6MPa to 0.5MPa when conditions of hydrogen peroxide bleachingremained unchanged and wheat straw pulp achieved the same whiteness. Hydrogen peroxide consumption decreased from 2% to 1.8% when oxygen bleaching has the same conditions and achieved the same white degree.