Observation of generalized Kibble-Zurek mechanism across a first-order quantum phase transition in a spinor condensate

The Kibble-Zurek mechanism provides a unified theory to describe the universal scaling laws in the dynamics when a system is driven through a second-order quantum phase transition. However, for first-order quantum phase transitions, the Kibble-Zurek mechanism is usually not applicable. Here, we experimentally demonstrate and theoretically analyze a power-law scaling in the dynamics of a spin-1 condensate across a first-order quantum phase transition when a system is slowly driven from a polar phase to an antiferromagnetic phase. We show that this power-law scaling can be described by a generalized Kibble-Zurek mechanism. Furthermore, by experimentally measuring the spin population, we show the power-law scaling of the temporal onset of spin excitations with respect to the quench rate, which agrees well with our numerical simulation results. Our results open the door for further exploring the generalized Kibble-Zurek mechanism to understand the dynamics across first-order quantum phase transitions.

Transfer potentials of antibiotic resistance genes in Escherichia spp. strains from different sources

Multidrug-resistant Escherichia coli and antibiotic-resistance genes (ARGs) present a danger to public health. However, information on the dissemination potentials of antibiotic resistance among bacteria from different environments is lacking. We isolated multiple antibiotic-resistant Escherichia spp. from animal farms, hospitals, and municipal wastewater-treatment plants (MWWTPs) using culture-based methods, and carried out resistance phenotype and gene analyses. Thirty-five isolates of multiple antibiotic-resistant Escherichia spp. were further screened to detect 61 ARGs, 18 mobile genetic elements (MGEs), and gene cassettes. The isolates from livestock manure and MWWTPs showed greater diversity in plasmid profiling than hospital wastewater. Each Escherichia sp. carried 21-26 ARGs and 8-12 MGEs. In addition, 11 gene cassettes were detected in 34 Escherichia isolates, with greater diversity in livestock manure and MWWTPs than in hospital wastewater. The results indicated that the potential for ARG transfer was higher in livestock manure and MWWTPs compared with human clinical sources, possibly related to the high occurrence of both residual antibiotics and heavy metals in these environments.

[Co-prevalence relationship analysis on different metabolic syndrome scores and behavioral risk factors in adults from Urumqi based]

Objective: To investigate the influence of the prevalence and co-prevalence of risk factors for metabolic syndrome on the scores of different levels of metabolic syndrome in people receiving physical examination in Urumqi. Methods: Using the 2017 Xinjiang Health Examination Database, a total of 175 927 people from 7 districts and 1 county in Urumqi were selected as subjects. Face-to-face survey and body measurements were used to collect cardiovascular risk factors and metabolic syndrome scores. Metabolic syndrome scores were used. For the 0-5 points at 6 levels, χ(2), χ(2) trend test, correlation analysis of ordered variable Kendall's tau-b, and logistic regression analysis of ordered results were used to analyze the influence of prevalence and co-prevalence of behavioral risk factors on the MS scores. Results: The percentages of 6 metabolic syndrome scores in the sample population were 23.82%, 27.87%, 22.41%, 16.03%, 8.02%, and 1.85%, respectively. The scores of metabolic syndrome were different in different age groups, ethnic groups, groups with different drinking rates, and groups with different dietary types, with the differences all significant (P<0.05).The MS score in men increased with the increase of oil/salt rate and excessive drinking rate (P<0.01). The score in women increased with the increase of the current smoking rate, oil/salt rate, and increased with the decrease of physical activity (P≤0.01). There was no significant difference in the distribution of regular drinking rates between different score groups (P>0.05). The scores of metabolic syndrome increased with the increase of risk factors (P<0.05). Ordered results logistic analysis found that in the men with ≥3 risk factors and the metabolic syndrome score was 1.15 (1.06-1.26) times higher than that in the men without risk factor, as well as in women with 2 risk factors and≥3 risk factors. The metabolic syndrome scores were 1.38 (1.22-1.55), 2.02 (1.53-2.66) times higher than those in the women without risk factors. Conclusions: The physical examination group in Urumqi, the more the metabolic syndrome disease behavior risk factors clustered, the higher the metabolic syndrome score was. Therefore, comprehensive intervention measures should be taken to control the different forms of metabolic syndrome to prevent the occurrence and progress of the disease.

A multiple-step strategy for screening Saccharomyces cerevisiae strains with improved acid tolerance and aroma profiles

Acid tolerance and aroma profile are crucial factors for wine production in Saccharomyces cerevisiae. However, most wine yeasts to date fail to endure low-pH environments, therefore resulting in problems such as lengthened fermentation and poor flavor during acidic fruit wine production. In the present study, we established a multiple-step screening strategy, which was composed of atmospheric and room temperature plasma (ARTP), high-throughput screening (HTS), and laboratory adaptive evolution (ALE), to screen yeast strains for potential wine-producing with enhanced performances during low pH conditions. Importantly, we obtained the S. cerevisiae strain from the mutant library, ET008-c54, which displayed exhibited excellent performances in survival rate, fermentation time, aroma profile, and genetic stability. More specifically, the survival rate of ET008-c54 at low pH was increased by 10-fold, the fermentation time of greengage plum wine was shortened by about 70%, and the content of main aroma compounds was significantly increased by 52%. Collectively, we demonstrate the practical application of the screening platform designed for discovering mutant strains in winemaking technology.

Observation of Dynamical Quantum Phase Transitions with Correspondence in an Excited State Phase Diagram

Dynamical quantum phase transitions are closely related to equilibrium quantum phase transitions for ground states. Here, we report an experimental observation of a dynamical quantum phase transition in a spinor condensate with correspondence in an excited state phase diagram, instead of the ground state one. We observe that the quench dynamics exhibits a nonanalytical change with respect to a parameter in the final Hamiltonian in the absence of a corresponding phase transition for the ground state there. We make a connection between this singular point and a phase transition point for the highest energy level in a subspace with zero spin magnetization of a Hamiltonian. We further show the existence of dynamical phase transitions for finite magnetization corresponding to the phase transition of the highest energy level in the subspace with the same magnetization. Our results open a door for using dynamical phase transitions as a tool to probe physics at higher energy eigenlevels of many-body Hamiltonians.

[Effect of low concentration paraquat on activation of mouse microglia M1/M2 phenotypes]

Objective: To observe the effect of low concentration paraquat (PQ) on activation and phenotypic M1/M2 polarization of mouse microglia cells (BV2) . Methods: BV2 cells were used as model, and cultured in vitro were exposed to paraquat at designed concentrations of 0, 0.015, 0.03, 0.06, 0.12, 0.24, 0.48 μmol/L and 0.05 μmol/L 1-methyl-4-phenylpyridinium (MPP(+)) for 24 h, and cell viability was determined by CCK8 assay. After induced by 0, 0.015, 0.03, 0.06, 0.12 μmol/L PQ and 0.05 μmol/L MPP(+) for 24 h, the contents of tumor necrosis factor-α (TNF-α) , interleukin-6 (IL-6) and IL-1β in cell culture supernatant were determined by enzyme-linked inmunosorbent assay (ELISA) . Cell migration ability was determined by transwell. Immunofluorescence (IF) and flow cytometry were used to determine the phagocytic capacity of cells. Designed concentrations of 0, 0.03, 0.06, 0.12 μmol/L PQ and 0.05 μmol/L MPP(+) for 24 h, the protein expressions of M1 markers of BV2 (TNF-α, IL-6, IL-1β, Nitric oxide synthase-iNOS, CD86) and M2 markers of BV2 (Arginase type-1 Arg-1 and Mannose recepteor-CD206) were determined by Western Blot after PQ expourse (0, 0.03, 0.06, 0.12 μmol/L) and 0.05 μmol/L MPP(+) induction. Results: Compared with 0 μmol/L PQ group, proliferation activity of BV2 cells was significantly increased by 0.03~0.12 μmol/L PQ while inhibited by 0.48 μmol/L PQ (P<0.05) . The cell proliferation activity of cells treated with 0.03 μmol/L PQ was significantly increased in 24 hours (P<0.05) . ELISA showed that TNF-α, IL-6 and IL-1β contents in the cell supernatant of the PQ group were significantly higher than those of 0 μmol/L PQ group, especially in 0.03 and 0.06 μmol/L PQ exposed group (P<0.05) . The results of IF and flow cytometry showed that phagocytic capacity of 0.015, 0.03 and 0.06 μmol/L PQ group was significantly enhanced compared with 0 μmol/L PQ group (P<0.05) . Transwell showed that the cell invasion ability of 0.03, 0.06, 0.12 μmol/L PQ was significantly higher than that of 0 μmol/L PQ group (P<0.05) . Western blot showed that compared with 0 μmol/L PQ group, the expression levels of M1 markers TNF-α, IL-6, IL-1β, iNOS and CD86 were significantly increased in 0.03 and 0.06 μmol/L PQ exposed group, while the expression levels of M2 markers Arg-1 and CD206 protein were decreased in 0.06 and 0.12 μmol/L PQ exposed group (P<0.05) . Conclusion: Low concentration PQ can abnormally activate BV2 cell, making the transformation of BV2 cell into pro-inflammatory M1 type and inhibiting its transformation into anti-inflammatory M2 type.

Metabolomics Changes of Serum in Rats Dying from Untypical Electric Injury

Abstract

Objective To study the differential metabolites of serum in rats dying from untypical electric injury by ¹H nuclear magnetic resonance （¹ NMR）-based metabolomics methods, in order to provide clues for identification of death from antemortem untypical electric injury and instant postmortem electric injury. Methods Models of rats dying from untypical electric injury, instant postmortem electric injury, mechanical asphyxia, mechanical injury, and high temperature injury were established. The rats in control group were executed without any treatment. The serums of rats from every group were detected by ¹H NMR-based metabolomics technology to screen differential metabolites. Results The rats dying from untypical electric injury group was compared with those from mechanical asphyxia group, mechanical injury group, high temperature injury group, and control group, respectively. Four chemical shift points with diagnostic value, and their corresponding metabolites were screened. These chemical shift points contained many small molecules, such as alcohols, phenols, sugars, amino acids, etc. The death from untypical electric injury group was compared with those from instant postmortem electric injury group and control group, and then eight chemical shift points with diagnostic value and their corresponding metabolites were screened. These chemical shift points contained small molecules, such as sugars, amino acids, esters, nucleic acids, etc. Conclusion The ¹H NMR-based metabolomics technology can identify differential metabolites of serum in rats dying from untypical electric injury, therefore it may provide a basis for the diagnosis of death from untypical electric injury and the identification of antemortem electric injury and instant postmortem electric injury.

Endophytic Bacillus velezensis strain B-36 is a potential biocontrol agent against lotus rot caused by Fusarium oxysporum

AIM

The aim of this study was to screen potential lotus plant endophytic bacterial isolate for effective inhibition against lotus rot causing fungal pathogen Fusarium oxysporum.

METHODS AND RESULTS

In this study, endophytic bacteria were isolated from lotus tissues and tested for antagonistic activities against the pathogenic fungus F. oxysporum. Among the putative endophytic Bacillus strains identified, suspensions of the strain B-36 showed the highest inhibition rate against F. oxysporum growth. Pot assays indicated that B-36 was effective in controlling F. oxysporum-inducing lotus rot. However, the control efficiency varied with the inoculation method and concentration, where injection of 800 μl B-36 suspension per plant (2 × 10⁸  CFU per ml) into stems showed the highest control efficiencies of 77·1 and 60·0% for pre-inoculation and post-inoculation. In addition, the colonizing population levels (CPLs) of B-36 on lotus also varied with the inoculation method and concentration, with the highest CPLs, that is, 3·05 and 2·83 log(CFU per gram), being observed on lotus leaves and stems respectively for stem injection of 200 μl per plant. Moreover B-36 showed no noticeable effects on lotus seed germination rate or seedling growth. Finally, B-36 was characterized as Bacillus velezensis based on its morphology, Gram-positive characteristics, as well as its 16S rDNA and gyrB sequences.

CONCLUSION

The isolate B-36 can be applied as a biocontrol agent against F. oxysporum-inducing lotus rot.

SIGNIFICANCE OF IMPACT OF THE STUDY

The soil-borne fungus F. oxysporum causes lotus rot and severe yield loss, and currently available control methods are very limited. Here we identify a new promising biocontrol agent against lotus rot caused by F. oxysporum.

[Clinical analysis of secondary hemophagocytic lymphohistiocytosis complicated with capillary leak syndrome]

目的

探讨继发性噬血细胞性淋巴组织细胞增多症（sHLH）合并毛细血管渗漏综合征（CLS）的临床特征。

方法

回顾性分析2015年1月至2017年12月江苏省人民医院收治的87例sHLH患者的临床及实验室资料，其中21例合并CLS（CLS-sHLH组），66例未合并CLS（非CLS-sHLH组）。比较两组的临床表现、实验室检查、治疗及预后差异。

结果

比较CLS-sHLH组和非CLS-sHLH组患者引起sHLH的病因，差异无统计学意义（P>0.05）。CLS-sHLH组患者ANC、血清纤维蛋白原、白蛋白较非CLS-sHLH组降低，而甘油三酯较非CLS-sHLH组升高（P值均<0.05）。CLS-sHLH组患者均有不同程度水肿、体重增加、低血压、低蛋白血症、少尿及多浆膜腔积液。其中15例患者CLS症状消失，CLS中位好转时间为7（5~14）d。6例患者CLS症状未消失，并于15（6~30）d死亡。CLS-sHLH组中位OS时间低于非CLS-sHLH组（75 d对未达到，P=0.031）。

结论

在sHLH患者中，CLS的发生可能与sHLH的原发病无明显相关。严重的ANC、纤维蛋白原及白蛋白减低，甘油三酯升高，可能是sHLH发生CLS的伴随症状。sHLH合并CLS时预后差。

[Three patients with large area burns complicated by acute acalculous cholecystitis]

From April 2017 to April 2018, three male patients aged 46-71 years with large area burns were treated in our hospital. Acute acalculous cholecystitis (AAC) symptoms of the patients began to appear 15-81 days after injury. AAC was diagnosed 24-81 days after injury. Ultrasound-guided percutaneous transhepatic cholecystostomy was performed 26-82 days after injury. The symptoms subsided in 2 patients, and cholecystectomy was performed in 1 patient with gallbladder perforation 94 days after injury. The patients were cured and discharged 41-118 days after injury. No recurrence of cholecystitis occurred during 8-9 months of follow-up after discharge.

[The association between corneal biomechanical parameters and visual field progression in patients with normal tension glaucoma]

Objective: To evaluate the association between corneal biomechanical parameters and visual field (VF) progression in normal tension glaucoma (NTG) using the Corvis-ST device, and to evaluate the ability of corneal biomechanical parameters to predict the VF progression. Methods: Corneal biomechanical parameters of newly diagnosed NTG patients were obtained using Corvis-ST in the baseline follow-up visit. The VF progression was defined as a 4-point increase in the Advanced Glaucoma Intervention Study (AGIS) score compared to the baseline in three consecutive follow-up visits (per 3-6 months). Corneal biomechanical parameters were compared between progressive and nonprogressive VF loss eyes using the independent-sample t test and Mann-Whitney U test. Spearman correlation analysis was used to explore the relationship between the corneal biomechanical parameters and the VF progression. Receiver operating characteristic curves were studied for the parameters and the sensitivity and specificity for distinguishing between progressive and nonprogressive glaucomatous eyes. The areas under the receiver operating characteristic curves (AUC) were also evaluated. Results: Sixty patients with NTG were enrolled in this study. Among them, 12 were lost to follow-up. A total of 48 patients completed all follow-up visits on schedule. Eleven of them were excluded due to one or more uncontrolled intraocular pressure (IOP) during the follow-up (less than 30% IOP reduction from the baseline). Thirty-seven eyes of 37 diagnosed NTG patients were enrolled. Ten eyes reached a progression endpoint. There was no significant difference in age, central corneal thickness, axial length, baseline IOP or baseline VF between the two groups. There was significant difference in Time A1 [(7.10±0.17) ms vs. (7.37±0.28) ms, t=-3.357, P=0.002], Length A1 [1.74(1.61, 1.77) mm vs. 1.78(1.77, 1.79) mm, Z=-3.036, P=0.002], Velocity A1 [0.16(0.14, 0.16) m/s vs. 0.15(0.14, 0.15) m/s, Z=-2.627, P=0.009] and DefAmpl HC [(1.22±0.13) mm vs. (1.12±0.11) mm, t=2.601, P=0.013] between progressive and nonprogressive glaucomatous eyes. Correlation analysis showed that Time A1, Length A1, Velocity A1 and DefAmpl HC were correlated with VF progression (r=-0.521, -0.463, 0.401, 0.349, P<0.05) . Time A1 demonstrated the highest AUC (0.817, P=0.001), followed by Length A1 (0.780, P=0.003), Velocity A1 (0.734, P=0.012) and DefAmpl HC (0.713, P=0.022). The cut-off set of Time A1 was 7.2 ms, the sensitivity was 80.0%, and the specificity was 82.8%. Conclusions: There were differences in corneal biomechanical parameters between eyes with progressive and nonprogressive VF loss in patients with NTG. There were lower Time A1 and Length A1 values and higher Velocity A1 and DefAmpl HC values in progressive glaucomatous eyes. This indicates a quicker response to reach first degree applanation and a larger degree of corneal deformability in progressive eyes. It is predicted that the easier deforming of the cornea, the smaller tolerance of the sclera and lamina cribros on IOP, making the optic disc more vulnerably. This may be one of the causes of glaucomatous optic nerve damage. Time A1 was the best parameter to predict the progression of VF among the corneal biomechanical parameters obtained by Corvis-ST. (Chin J Ophthalmol, 2018, 54: 171-176).

Physicochemical characterization and quality of Dangshan pear wines fermented with different Saccharomyces cerevisiae

Three commercial yeasts strains, namely, Saccharomyces cerevisiae SY, DV10, and Drop Acid Yeast, were used for Dangshan pear wine fermentation. Monitoring main physical and chemical indexes and scoring comprehensive sensory characteristics to find a suitable yeast to produce Dangshan pear wine. The fermentation cycle of SY was short (15 days), and the SY-fermented wine had a suitable sugar-acid ratio, with a residual sugar content of 3.13 ± 0.05 g/L, total acid content of 3.40 ± 0.11 g/L, and ethanol content of 14.1 ± 0.27% (v/v). Additionally, 42 flavor compounds were detected in fermented Dangshan pear wine, and the total amount of flavor compounds was highest in the SY wine (2,584.72 μg/L). Combined with the comprehensive sensory evaluation scores, these results suggest that Saccharomyces cerevisiae SY was the most suitable strain to produce Dangshan pear wine. PRACTICAL APPLICATIONS: In this study, we compared the physical and chemical indicators of pear wine brewed by different Saccharomyces cerevisiae in the process of fermentation and the final quality of pear wine products. It was concluded that the pear wine produced by Saccharomyces cerevisiae SY had good quality. The study found a strain suitable for the fermentation of pear wine and provided a theoretical basis for the industrial production of pear wine. Next, we can try to use Saccharomyces cerevisiae SY for large-scale production of pear wine and try to sell it on the market.

[Clinical effect of nano-fat mixed granule fat transplantation in the treatment of cicatricial facial depression and atrophy and the related experimental mechanism]

Objective: To study the clinical effect of nano-fat mixed granule fat transplantation in the treatment of cicatricial facial depression and atrophy, and to explore the related experimental mechanism. Methods: (1) From January 2012 to April 2018, 105 patients conforming to the inclusion criteria, with cicatricial facial depression and atrophy deformity who needed facial fat transplantation, were admitted to our unit. Their medical records were analyzed retrospectively. According to the patients' wishes, 54 patients (12 males and 42 females) aged 10-59 years received traditional transplantation of pure autologous granule fat collected from abdomen/thigh and were included in simple transplantation group, while the other 51 patients (14 males and 37 females) aged 7-63 years received transplantation of autologous nano-fat mixed granule fat collected from abdomen/thigh and were included in mixed transplantation group. The treatment satisfaction of patients 3 and 6 months after operation was assessed by the facial fullness, symmetry, scar, and complications using self-made scales and photo data before and after operation. Six months after operation, the patients were assessed whether they needed to undergo a second operation, and the rate of second operation was calculated. During the second operation, the fat of patients transplanted in the first operation was collected, and the morphology of adipocytes and microangiogenesis was observed under a scanning electron microscope. (2) Adipose-derived stem cells (ADSCs) were isolated and cultured from abdominal fat of a 4-week-old male Sprague-Dawley (SD) rat. The 5th passage of cells were selected to observe cell morphology after cultured for 14 days, observe expression of vimentin and cytokeratin-18 by immunofluorescence method, identify osteogenic and adipogenic differentiation, and detect rates of CD29 and CD44 positive cells by flow cytometer (n=3). Eighteen 4-week-old male SD rats were divided into ADSCs transplantation group, simple scar group, and blank control group according to the random number table, with 6 rats in each group. Rats in ADSCs transplantation group and simple scar group were subcutaneously injected with 1 mL bleomycin which was dissolved in phosphate buffered saline (PBS) with a mass concentration of 1 mg/mL at the back to establish scar models. After 3 hours, rats in ADSCs transplantation group were injected with 1×10(6) ADSCs suspended in 0.1 mL PBS at the same injection site, while rats in simple scar group were injected with 0.1 mL PBS. Rats in blank control group were injected with the same doses of PBS in the same place at the same two time points mentioned above. After continuous injection for 28 days in each group, the full-thickness skin tissue of the injected area of all rats was collected to observe the collagen fibers by Masson staining and expressions of α-smooth muscle actin (α-SMA) and transforming growth factor β(1) (TGF-β(1)) by immunohistochemistry, and the positive cells were counted. Data were processed with Mann-Whitney U test, χ(2) test, one-way analysis of variance, and least significant difference test. Results: (1) Compared with the preoperative condition, the facial fullness and symmetry of patients in simple transplantation group were better in 3 months after operation, with scar color closer to the surrounding skin, and the filling volume of patients in this group decreased in 6 months after operation as compared with that in 3 months after operation. In mixed transplantation group, the facial fullness and symmetry of patients were better in 3 and 6 months after operation as compared with the preoperative condition, with scar color and texture closer to the surrounding skin, and the filling volume in 6 months after operation was not obviously reduced as compared with that in 3 months after operation. Fat liquefaction and subcutaneous nodule formation occurred respectively in 1 patient in simple transplantation group within 3 months after operation. The treatment satisfaction of patients in mixed transplantation group was significantly higher than that in simple transplantation group in 3 and 6 months after operation (Z=-2.566, -3.084, P<0.05 or P<0.01). Six months after operation, the second operation rate of patients in mixed transplantation group was 7.84% (4/51), which was significantly lower than 22.22% (12/54) in simple transplantation group (χ(2)=4.199, P<0.05). At the second operation, compared with those of simple transplantation group, the cells of fat transplanted in the first operation of patients in mixed transplantation group were more plump, without collapse or dryness, and the cells were closely arranged, with smaller gap; the tubular and the cord-like microvascular structure on the cell surface were more abundant, and the cell gap was full of network-like microvascular structure that grew into the adipose tissue. (2) The fifth passage of cells isolated and cultured from rat fat grew adherently to the wall, with long fusiform or spindle shape, showing shoal-of-fish-like growth. Vimentin and cytokeratin-18 were highly expressed in the cells. Cells showed osteogenic and adipogenic differentiation ability by induction. The positive expression rates of CD29 and CD44 were higher than 90.00%. The cells were identified as ADSCs. After 28 days of injection, the collagen fibers in the dermis of skin tissue at the injection area of rats in blank control group were finely arranged. In simple scar group, a large amount of collagen was deposited in the dermis of skin tissue at the injection area of rats, the fiber bundles were thick and loosely unevenly arranged, and a large number of inflammatory infiltration and scattered muscle fibers were observed. In ADSCs transplantation group, the collagen fibers in the dermis of skin tissue at the injection area of rats were thicker than those of blank control group, with still neat arrangement, and a small amount of scattered muscle fiber and inflammatory infiltration was observed. After 28 days of injection, the expression of α-SMA in ADSCs transplantation group was mainly in microvessels in the dermis of skin tissue at the injected area of rats, and the number of α-SMA and TGF-β(1) positive cells was (49±12) and (63±10) cells per 20-fold field of view, respectively, which was similar to (35±16) and (44±17) cells per 20-fold field of view of blank control group (P>0.05), all significantly less than (135±13) and (121±23) cells per 20-fold field of view of simple scar group (P<0.05). Conclusions: Compared with those of autologous simple granule fat transplantation, autologous nano-fat mixed granule fat transplantation has better filling fullness in the treatment of patients with scar facial depression and atrophy. The filling effect lasts longer, and the improvement of scar texture is more obvious. As showed in the rat scar model experiment, the mechanism may be that ADSCs inhibit the expressions of α-SMA and TGF-β(1), thus inhibiting the formation of scar.

[Rush poppers use and risks of human papillomavirus infection among men who have sex with men in Urumqi: mediation effect through high-risk sexual behaviors]

Objective: To study the prevalence of rush poppers use among men who have sex with men (MSM) in Urumqi and to analyze the mediating effect of high-risk sexual behavior between the use of rush poppers and human papillomavirus (HPV) infection. Methods: From January to June 2018, 651 MSM were recruited through network and publicity. Data was collected by using online questionnaire and anal swab were collected from them for HPV genotyping. According to Baron and Kenny's criterion, multivariate logistic regression models was used to analyze the mediation effect of high-risks sexual behaviors (multiple sexual partners, anal intercourse condom use) between rush poppers use and HPV infection. Results: A total of 651 subjects were (32.0±8.0) years old, and 174 subjects (26.7%) had ever used rush poppers in the past 6 months, while 350 subjects (46.9%) had more than 2 sexual partners and 188 subjects (28.9%) did not use anal condom. After adjusting age and marital status, rush poppers use was associated with HPV infection (OR (95%CI) was 2.34 (1.63-3.36), P<0.05), and sexual partners in the past 6 months (OR (95%CI) was 2.72 (1.89-3.93), P<0.05).After adjustment for age, marital status, sexual partners in the past 6 months, and anal condom use, rush poppers use was still associated with HPV infection (OR (95%CI) was 2.21 (1.53-3.19), P<0.05).After adjustment and adjustment of age, marital status, rush poppers use and anal sex condom use, the number of sexual partners at nearly 6 months was still associated with HPV infection (OR (95%CI) was 1.46 (1.05-2.04), P<0.05). Conclusion: Sexual partners in the past 6 months have a mediation effect between rush poppers use and HPV infection in Urumqi. For the prevention of sexually transmitted diseases, we should focus on rush poppers use.