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The peroxide value and acid value in edible vegetable oil were determined by automatic potentiometric titration. Through the establishment of uncertainty mathematical model, the uncertainty components and expanded uncertainty affecting the peroxide value and acid value measurement results were analyzed and calculated. The test results showed that the average peroxide value of the edible vegetable oil was 1.22 mmol/l, the average acid value was 1.43 mg/g, the expanded uncertainty of peroxide value was 0.016 mmol/l, the expanded uncertainty of acid value was 0.044 mg/g, the confidence factor k = 2, and the repeatability of measurement was the main factor affecting the uncertainty of the test results of peroxide value and acid value.

Aerodynamic and acoustic experiments were carried out to investigate the induced inflow distribution and noise characteristics of a scissors rotor in hover. The aerodynamic experiment was conducted on a model rotor rig and the induced inflows for two different scissors rotor configurations (the L configuration and U configuration) were measured. The experimental results indicate that the induced velocity near the lower blades is consistently larger than that near the upper blades. A free-wake analysis was used to predict the aerodynamic characteristics. The variation of the induced velocity with different scissors angles was simulated analytically and the results were compared with test data. The acoustic experiment was conducted in an anechoic aeroacoustic laboratory and the noise levels for both the scissors rotor configuration and a conventional configuration were measured. The effects of different scissors angles on rotor noise were investigated. It was shown that the noise level of a scissors rotor depends on both the azimuthal and vertical spacing and is not necessarily less than that of a conventional configuration.

To promote the growth of Casuarina equisetifolia and address the abnormalities in the structure and function of rhizosphere soil microbial community, we isolated eight strains with multiple functions from the root nodules of C. equisetifolia , including nitrogen fixation (N), production of cell wall-degrading enzymes (protease and cellulase), auxin (IAA) production, siderophore production, ammonia (NH 3 ) production, and phosphate solubilization. Among these strains, LB08, LB18, LB19, LB42, LB46, LB63, and LB69 were identified as Paenibacillus species, while LQ10 was identified as a Brucella sp. Results of seed soaking experiments showed that all the eight strains promoted the growth of C. equisetifolia seedlings. Strain LB69 significantly increased the germination rate and seedling vigor by 19.7% and 28.3%, respectively. Strain LQ10 significantly enhanced root length and root vigor by 48.2% and 334.4%, respectively. Strains LB18 and LB42 had the strongest effects on early shoot length and biomass accumulation, with increases of 22.4% and 32.8%, respectively. After seed soaking, the number of isozymes bands of polyphenol oxidase, superoxide dismutase, and peroxidase increased, with some bands showing enhanced intensity and increased diversity of enzyme isoforms, thereby enhancing stress resistance. In summary, the addition of these eight strains promoted plant growth and antioxidant enzyme activity, indicating their potential role as biofertilizers.

Objectives: This study aimed to compare and analyze the consistency and difference between metageno-mic next-generation sequencing (mNGS) and conventional bacterial culture in the detection of pathogenic microorganisms in maxillofacial space infection, as well as to provide a new detection method for the early clinical identification of pathogenic bacteria in maxillofacial space infection., Methods: The clinical data of 16 patients with oral and maxillofacial space infections in the First Affiliated Hospital of Zhengzhou University from March 2020 to June 2020 were collected. mNGS and conventional bacterial culture methods were used to detect pus. We then analyzed and compared the test results of the two methods, including the test cycle, positive detection rate, anaerobic bacteria, facultative anaerobes and aerobic bacteria detection rates, distribution of pathogenic bacteria, relative species abundance, and resistance genes., Results: The average inspection period of mNGS was (18.81±3.73) h, and the average inspection period of bacterial culture was (83.25±11.64) h, the former was shorter than the latter ( P <0.05). The positive detection rate of mNGS was 100% (16/16), and the positive detection rate of conventional bacterial culture was 31.25% (5/16), the former was higher than the latter ( P <0.05). The detection rate of mNGS anaerobic bacteria was 93.75% (15/16), the detection rate of bacterial culture anaerobes was 0 (0/16), the former was higher than the latter ( P <0.05). Using mNGS, the detection rate of facultative anaerobes in bacterial culture was 75.00% (12/16), and the detection rate of facultative anaerobes in bacterial culture was 25.00% (4/16), the former was higher than the latter ( P <0.05). The detection rate of aerobic bacteria in bacterial culture was 12.50% (1/16), the former was higher than the latter ( P >0.05). mNGS detected 15 kinds of pathogenic bacteria, among which 3 were Gram positive, 12 were Gram negative, 49 were non-pathogenic, 16 were Gram positive, and 32 were Gram negative, 1 was fungus., Conclusions: Compared with conventional bacterial culture, mNGS has the characteristics of short test time, high sensitivity, and high accuracy. Thus, it is a new detection method for the early identification of pathogenic bacteria in maxillofacial space infection and is beneficial to the early clinical diagnosis and treatment of the disease.

The aim of this study was to investigate the effect of diallyl disulfide (DADS) on the apoptosis of K562 cells and to explore the mechanism of K562 apoptosis induced by DADS. The K562 cells were treated with different concentrations of DADS for 24, 48 and 72 hours. The concentrations of DADS were as follows: 0 (control group), 10, 20, 40 and 80 mg/L. The morphologic changes of leukemia K562 cells treated with DADS were observed by Hoechst33 258 staining. The apoptosis of K562 cells treated with different concentrations of DADS for 24, 48 and 72 hours was analyzed by flow cytometry. The mRNA expression changes of Fas and FasL were detected by reverse transcription-polymerase chain reaction (RT-PCR) after K562 cells were treated with different concentrations of DADS for 48 hours. The results indicated that the characteristics of apoptosis in K562 cells induced by DADS were as follows: reduction of nucleus, chromatin condensation and nuclear membrane rupture. The flow cytometry with PI straining showed that after 24 hours of DADS treatment the apoptosis rate of K562 cells increased from 11.60 ± 0.83% at the concentration of 10 mg/L to 37.94 ± 0.87% at the concentration of 40 mg/L. The apoptosis rate of K562 cells increased from 37.94 ± 0.87% (24 hours) to 47.02 ± 0.66% (72 hours) after treatment with DADS of 10 mg/L increasing to 40 mg/L DADS. The Fas mRNA expression levels of the related apoptotic genes increased after K562 cells were treated with different concentrations of DADS for 48 hours, while FasL mRNA expression decreased significantly after DADS treatment for 48 hours, compared with those in the control group (p < 0.05). It is concluded that DADS can induce the apoptosis of human leukemia K562 cells in a time-and concentration-dependent manners. The activation of Fas/FasL pathway may play an important role in the K562 cell apoptosis induced by DADS, which is associated with increasing Fas gene expression and decreasing FasL gene expression.

Objective: To study the effects of diallyl disulfide (DADS) on apoptosis of human leukemia K562 cells and possible mechanisms., Methods: The morphologic changes of leukemia K562 cells after DADS treatment were observed by Hoechst 33258 staining. Cell apoptosis rates after different concentrations and different durations of DADS treatment were determined by flow cytometry. Fas, FasL and caspase-8 mRNA expression was estimated by reverse transcription-polymerase chain reaction (RT-PCR) 48 hrs after DADS treatment., Results: The characteristics of apoptosis in K562 cells induced by DADS were observed. After 24 hrs of DADS treatment, the apoptosis rate of K562 cells increased from (11.60 ± 0.83)% at the concentration of 10 mg/L to (37.94 ± 0.87)% at the concentration of 40 mg/L. The apoptosis rate of K562 cells increased after 40 mg/L DADS with the increasing time from (37.94 ± 0.87)% (24 hrs) to (47.02 ± 0.66)% (72 hrs). Expression of Fas and caspase-8 mRNA increased, while FasL mRNA expression decreased significantly 48 hrs after DADS treatment compared with the control group (P<0.05)., Conclusions: DADS can induce apoptosis of human leukemia K562 cells in a time- and concentration-dependent manner, possibly through increasing Fas and caspase-8 expression and decreasing FasL expression.