[Survey on the awareness rate of mpox knowledge and related factors among men who have sex with men in China]

Objective: To understand the awareness rate of mpox knowledge and related factors among men who have sex with men (MSM) in China. Methods: The survey was conducted among men aged ≥18 years who had sex with men in the past year, using the convenience sampling method. The estimated sample size was 4 312. With the assistance of social organizations of MSM in 30 provinces in China, an online questionnaire survey was conducted using anonymous self-designed questionnaires powered by www.wjx.cn during 10-14 August 2023 to collect information on socio-demographic characteristics, awareness of mpox knowledge, travel history, and sexual behaviors of the respondents. The software SAS 9.4 was used for statistical analysis. Results: There were 7 725 respondents, and the age of the respondents was (31.6±9.0) years. The results revealed that the awareness rate of mpox knowledge was 50.1% (3 872/7 725). The main routes to acquire mpox knowledge were mainly new media, including WeChat, Weibo, TikTok, and Blued social software (88.4%,6 827/7 725), while official media report was the most trusted way to acquire related knowledge (79.3%,6 129/7 725). Multivariate logistic regression analysis revealed that the factors indicated a higher awareness rate of mpox knowledge, including living in the western region or the eastern region, people were over 26 years old in early adulthood and midlife, college-educated or with higher degrees, living in towns or urban periphery, being in homosexual or in bisexual relationships, 1-5 homosexual times/months in the past 3 months, knowing their HIV infection status, paying attention to mpox knowledge very often, occasionally or rarely, and convenient ways to acquire mpox knowledge from new media and social organizations. Conclusions: The awareness rate of mpox knowledge was low among MSM in China. Efforts should be made to improve the awareness rate of mpox knowledge among those who are young, less educated, or sexually active, with targeted health education via new media and social organizations.

[Clinical characteristics of hospitalized children with respiratory syncytial virus infection and risk prediction of severe illness during the post-COVID-19 era in Kunming]

Objective: To compare the epidemiological and clinical characteristics of hospitalized children with respiratory syncytial virus (RSV) infection in Kunming among the pre-and post-COVID-19 era, and to establish a prediction model for severe RSV infection in children during the post-COVID-19 period. Methods: This was a retrospective study. Clinical and laboratory data were collected from 959 children hospitalized with RSV infection in the Department of Pulmonary and Critical Care Medicine at Kunming Children's Hospital during January to December 2019 and January to December 2023. Patients admitted in 2019 were defined as the pre-COVID-19 group, while those admitted in 2023 were classified as the post-COVID-19 group. Epidemiological and clinical characteristics were compared between the two groups. Subsequently, comparison of the clinical severity among the two groups was performed based on propensity score matching (PSM). Furthermore, the subjects in the post-COVID-19 group were divided into severe and non-severe groups based on clinical severity. Chi-square test and Mann-Whitney U test were used for pairwise comparison between groups, and multivariate Logistic regression was applied for the identification of independent risk factors and construction of the prediction model. The receiver operating characteristic (ROC) curve and calibration curve were employed to evaluate the predictive performance of this model. Results: Among the 959 children hospitalized with RSV infection, there were 555 males and 404 females, with an onset age of 15.4 (7.3, 28.5) months. Of which, there were 331 cases in the pre-COVID-19 group and 628 cases in the post-COVID-19 group. The peak period of RSV hospitalization in the post-COVID-19 group were from May to October 2023, and the monthly number of inpatients for each of these months were as follows: 72 cases (11.5%), 98 cases (15.6%), 128 cases (20.4%), 101 cases (16.1%), 65 cases (10.4%), and 61 cases (9.7%), respectively. After PSM for general data, 267 cases were matched in each group. The proportion of wheezing in the post-COVID-19 group was lower than that in the pre-COVID-19 group (109 cases (40.8%) vs. 161 cases (60.3%), χ2=20.26, P<0.001), while the incidences of fever, tachypnea, seizures, severe case, neutrophil-to-lymphocyte ratio (NLR), C-reactive protein and interleukin-6 levels were all higher than those in the pre-COVID-19 group (146 cases (54.7%) vs. 119 cases (44.6%), 117 cases (43.8%) vs. 89 cases (33.3%), 37 cases (13.9%) vs. 14 cases (5.2%), 69 cases (25.8%) vs. 45 cases (16.9%), 3.6 (1.9, 6.4) vs. 2.3 (1.8, 4.6), 9.9 (7.1, 15.2) vs. 7.8 (4.5, 13.9) mg/L, 20.5 (15.7, 30.4) vs. 17.2 (11.0, 26.9) ng/L, χ2=5.46, 6.36, 11.47, 6.42, Z=4.13, 3.06, 2.96, all P<0.05). There were 252 cases and 107 cases with co-infection in the post-and pre-COVID-19 groups, respectively. The proportion of triple and quadruple infection in the post-COVID-19 group was higher than that in the pre-COVID-19 group (59 cases (23.4%) vs. 13 cases (12.1%), 30 cases (11.9%) vs. 5 cases (4.7%), χ2=5.94, 4.46, both P<0.05). Among the 252 cases with co-infection in post-COVID-19 group, the most prevalent pathogens involving in co-infections, in order, were Mycoplasma pneumoniae 56 cases (22.2%), Influenza A virus 53 cases (21.0%), Rhinovirus 48 cases (19.0%), Parainfluenza virus 35 cases (13.9%), and Adenovirus 28 cases (11.1%).The result of multivariate Logistic regression showed that age (OR=0.70, 95%CI 0.62-0.78, P<0.001), underlying diseases (OR=10.03, 95%CI 4.10-24.55, P<0.001), premature birth (OR=6.78, 95%CI 3.53-13.04, P<0.001), NLR (OR=1.85, 95%CI 1.09-3.15, P=0.023), and co-infection (OR=1.28, 95%CI 1.18-1.38, P<0.001) were independently associated with the development of severe RSV infection in the post-COVID-19 group. The ROC curve of the prediction model integrating the above five factors indicated an area under the curve of 0.85 (95%CI 0.80-0.89, P<0.001), with an optimal cutoff of 0.21, a sensitivity of 0.83 and a specificity of 0.80. The calibration curve showed that the predicted probability in this model did not differ significantly from the actual probability (P=0.319). Conclusions: In the post-COVID-19 era in Kunming, the peak in pediatric hospitalizations for RSV infection was from May to October, with declined incidence of wheezing and increased incidence of fever, tachypnea, seizures, severe cases, and rates of triple and quadruple co-infections. Age, underlying diseases, premature birth, NLR, and co-infection were identified as independent risk factors for severe RSV infection in the post-COVID-19 period. In this study, a risk prediction model for severe pediatric RSV infection was established, which had a good predictive performance.

[Analysis on the use of HIV post-exposure prophylaxis and related factors in men who have sex with men in Qingdao]

Objective: To understand the use of post-exposure prophylaxis (PEP) and analyze related factors among men who have sex with men (MSM) in Qingdao, and provide a reference for the AIDS prevention and control in this population. Methods: A cross-sectional survey conducted from April 2022 to February 2023. Relying on MSM social groups in Qingdao, a snowball sampling method was applied to recruit research subjects who met the inclusion criteria of age ≥18 years old, having had homosexual anal or oral sex in the past six months, and HIV-negative or infection status unknown. The sample size was estimated at 566. Data on demographic characteristics, sexual behavior characteristics, PEP use, and others of the research subjects was collected through on-site questionnaires. The logistic regression model was used to analyze the factors associated with using PEP. Results: A total of 811 participants were recruited, mainly aged 25-34 (53.6%, 435/811), unmarried (74.7%, 606/811), with an average monthly income of ≥5 000 yuan (52.2%, 423/811), and having lived in Qingdao for ≥10 years (75.6%, 613/811). The proportion of those who knew the HIV status of their sexual partners in the last six months was 67.1% (544/811), and those with HIV-positive partners were 3.6% (29/811). In the last six months, the proportion of participants who had group sex (86.4%, 701/811), unprotected anal sex (98.2%, 796/811), and use of club drugs (80.3%, 651/811) was high. Moreover, 28.4% (230/811) had used PEP. The multivariate logistic regression analysis showed that the factors related to the use of PEP included divorced or widowed (aOR=5.46,95%CI:1.96-15.17), average monthly income ≥5 000 yuan (aOR=2.04,95%CI:1.44-2.89), same-sex sexual orientation (aOR=0.40,95%CI:0.22-0.71), having HIV-positive sexual partners in the last six months (aOR=2.54,95%CI:1.13-5.71) and having been tested for HIV ≥3 times in the last six months (aOR=1.46,95%CI:1.04-2.06). Conclusions: The prevalence of risk behaviors among MSM in Qingdao was high, and the use of PEP was low. In the future, it is essential to increase HIV/AIDS prevention education among MSM, promote MSM to know the HIV status of their sexual partners, and reduce the prevalence of risk behaviors among this population. Additionally, explore medical insurance reimbursement plans for PEP to reduce utilization costs and promote the use of PEP by MSM after HIV exposure occurs as soon as possible.

[A cohort study of HIV infection in club drug abusers among men who have sex with men in Qingdao]

Objective: To understand and analyze the incidence of HIV infection in club drug abusers among men who have sex with men (MSM) in Qingdao and provide a reference for the prevention and intervention of this population. Methods: From March 2017 to July 2022, club drug abusers among MSM who are HIV-negative were recruited by snowball sampling of MSM social organizations in Qingdao, a prospective cohort was established, and a follow-up survey was conducted every six months, with the sample size estimated to be 436. The survey contents included demographic characteristics, sexual characteristics, AIDS knowledge awareness, club drug abuse, HIV testing, and other information. HIV infection was the outcome-dependent variable, and the interval between the recruitment into the cohort and the HIV infection was the time-dependent variable. Cox proportional hazards regression analysis was conducted to identify the related factors for HIV infection. Results: A total of 987 participants of club drug abusers among MSM were recruited during the baseline survey and 826 eligible participants were enrolled in this cohort. A total of 46 HIV infection cases were found, and the cumulative follow-up time was 1 960.68 person-years. The incidence of HIV infection was 2.35/100 person-years. The multivariate Cox regression analysis showed that <30 (aHR=3.04, 95%CI: 1.62-5.71) non-Shandong residents (aHR=2.29,95%CI:1.20-4.39) found their partners through offline (aHR=4.62,95%CI:2.05-10.41), homosexual sexual partners >4 (aHR=3.06,95%CI:1.59-5.88), condom broken during sex (aHR=2.24,95%CI:1.21-4.17) and hemorrhage sexual intercourse (aHR=2.56,95%CI:1.31-5.03) were significantly associated with HIV infection in this cohort. Conclusions: The incidence of HIV infection in club drug abusers among MSM in Qingdao is generally low, but knowledge and practice have separated, and the risk of HIV infection is high. The related factors of HIV infection included younger age, non-Shandong residents, finding their partners offline, multiple sexual partners, condom break during sex, and hemorrhage sexual intercourse; HIV-related behavioral intervention should be strengthened.

Search for Λ[over ¯]-Λ Baryon-Number-Violating Oscillations in the Decay J/ψ→pK^{-}Λ[over ¯]+c.c

We report on the first search for Λ[over ¯]-Λ oscillations in the decay J/ψ→pK^{-}Λ[over ¯]+c.c. by analyzing 1.31×10^{9}  J/ψ events accumulated with the BESIII detector at the BEPCII collider. The J/ψ events are produced using e^{+}e^{-} collisions at a center of mass energy sqrt[s]=3.097  GeV. No evidence for hyperon oscillations is observed. The upper limit for the oscillation rate of Λ[over ¯] to Λ hyperons is determined to be P(Λ)=[B(J/ψ→pK^{-}Λ+c.c.)/B(J/ψ→pK^{-}Λ[over ¯]+c.c.)]<4.4×10^{-6} corresponding to an oscillation parameter δm_{ΛΛ[over ¯]} of less than 3.8×10^{-18}  GeV at the 90% confidence level.

[A cohort study of incidence of club drug abuse in men who have sex with men in Qingdao]

Objective: To understand and analyze the incidence of club drug abuse and influencing factors in men who have sex with men (MSM) in Qingdao, and provide reference for the AIDS prevention and intervention in this population. Methods: From March 2017 to July 31, 2022, MSM who did not abuse club drug were recruited by snowball sampling of MSM social organizations in Qingdao, a prospective cohort was established, and a follow-up survey was conducted every 6 months. The survey collected the information about the MSM's demographic characteristics, sexual characteristics, club drug abuse and others. The incidence of club drug abuse was the outcome dependent variable and the interval between the recruitment into the cohort and the incidence of club drug abuse was the time dependent variable. Cox regression analysis was conducted to identify the influencing factors for club drug abuse. Results: A total of 509 MSM were recruited at baseline survey, and 369 eligible MSM were enrolled in this cohort. A total of 62 MSM began to abuse club drug during the study period, and the cumulative follow-up time was 911.54 person-years, the incidence of club drug abuse was 6.80/100 person-years. All the club drug abusers shared drugs with others in the first club drug abuse, and 16.13% (10/62) had mix-use of club drugs. The multivariate Cox proportional risk regression analysis showed that being students (aHR=2.17, 95%CI: 1.15-4.10), receiving no HIV testing or receiving 1 HIV testing during past 6 months (aHR=4.57, 95%CI:1.80-11.60; aHR=5.15, 95%CI: 2.83-9.36), having sex only with regular sexual partners during past 6 months (aHR=4.75,95%CI:2.32-9.75), having more than 4 homosexual partners (aHR=1.70, 95%CI:1.01-2.87) and abuse of club drug of sexual partners during past 6 months (aHR=12.78, 95%CI:3.06-53.35) were significantly associated with club drug abuse in the MSM. Conclusions: The incidence of club drug abuse was at a high level in the MSM cohort in Qingdao, indicating a high risk for HIV infection. Being student, receiving less HIV testing, having sex only with regular sexual partners, having more homosexual partners and abuse of club drug of sexual partners during past 6 months were risk factors for the incidence of club drug abuse in the MSM. Targeted surveillance and intervention measures should be strengthened to reduce the risk of club drug abuse in MSM.

[HIV self-testing and related factors in men who have sex with men in Shijiazhuang]

Objective: To understand HIV self-testing and related factors in men who have sex with men (MSM) in Shijiazhuang. Methods: From August to September 2020, convenient sampling was used to recruit MSM in Shijiazhuang. Online questionnaires were used to collect information about their demographic characteristics, sexual behaviors and HIV self-testing. logistic regression model was used to analyze the related factors associated with HIV self-testing. Results: In the 304 MSM respondents, 52.3% (159/304) had HIV self-testing in the past 6 months, and 95.0% (151/159) used fingertip blood HIV detection reagent. Self-purchase was the main way to obtain HIV testing reagents (45.9%, 73/159), followed by supply from MSM social organization (44.7%, 71/159). The reasons for having HIV self-testing were non-specific testing time (67.9%, 108/159) and privacy protection (62.9%,100/159), the reasons for having no HIV self-testing included inability of using (32.4%, 47/145), being unaware of HIV self-testing reagent (24.1%, 35/145), and worry about inaccurate self-testing results (19.3%, 28/145). Multivariate logistic regression analysis showed that being 18-29 years old (aOR=2.68, 95%CI: 1.20-5.94), obtaining free HIV self-testing kits in recent 6 months (aOR=8.61, 95%CI: 4.09-18.11) and making friends through Internet and social software (aOR=2.68, 95%CI: 1.48-4.88) were positive factors for having HIV self-testing. Conclusion: HIV self-testing is a more flexible and convenient way to detect HIV in MSM, and the promotion of HIV self-testing in MSM should be strengthened to further increase the HIV detection rate in this population.

Investigating the generation and propagation evolution of orange optical vortices using continuous-wave KGW Raman lasers with astigmatic mode transformations

Various high-order orange beams (HOBs) at 588 nm are produced via off-center pumped Nd:YVO₄/KGW Raman lasers. We experimentally confirm that the HOBs can be fairly sustained at the incident pump power of 2.88 W, where the average output powers are overall from 300 mW to 160 mW with increasing the off-center displacements from 0.14 mm to 0.21 mm. The HOBs are further transformed by using an astigmatic mode converter to generate a variety of structured lights with optical vortices. Moreover, theoretical wave functions are analytically derived to characterize the propagation evolution of the converted HOBs. The experimental patterns for all propagating positions are excellently reconstructed by the derived wave functions, and the evolution of phase structures is numerically calculated to manifest the robust optical vortices.

Direct Measurement of the Branching Fractions B(ψ(3686)→J/ψX) and B(ψ(3770)→J/ψX), and Observation of the State R(3760) in e^{+}e^{-}→J/ψX

We report a measurement of the observed cross sections of e^{+}e^{-}→J/ψX based on 3.21  fb^{-1} of data accumulated at energies from 3.645 to 3.891 GeV with the BESIII detector operated at the BEPCII collider. In analysis of the cross sections, we measured the decay branching fractions of B(ψ(3686)→J/ψX)=(64.4±0.6±1.6)% and B(ψ(3770)→J/ψX)=(0.5±0.2±0.1)% for the first time. The energy-dependent line shape of these cross sections cannot be well described by two Breit-Wigner (BW) amplitudes of the expected decays ψ(3686)→J/ψX and ψ(3770)→J/ψX. Instead, it can be better described with one more BW amplitude of the decay R(3760)→J/ψX. Under this assumption, we extracted the R(3760) mass M_{R(3760)}=3766.2±3.8±0.4  MeV/c^{2} , total width Γ_{R(3760)}^{tot}=22.2±5.9±1.4  MeV, and product of leptonic width and decay branching fraction Γ_{R(3760)}^{ee}B[R(3760)→J/ψX]=(79.4±85.5±11.7)  eV. The significance of the R(3760) is 5.3σ. The first uncertainties of these measured quantities are from fits to the cross sections and second systematic.

[Tends on HIV and syphilis prevalence and sexual behaviors among young students in China, 2015-2019]

Objective: To analyze the tends on HIV/syphilis prevalence and sexual behaviors using the HIV/AIDS sentinel surveillance data of young students in China from 2015 to 2019 and provide evidence for the formulation of HIV/AIDS prevention and control measures among young students. Methods: From 2015 to 2019, a nationwide continuous cross-sectional survey was conducted in cities where colleges and technical schools were concentrated in each province. Multi-stage cluster sampling with the simple size 800, anonymous questionnaire, and blood sample collection were implemented to achieve general demographic information, sexual behavior, and serological information, analyze the trends and influence on HIV/syphilis infection and behaviors. Results: During 2015-2019, there was no linear trend on the antibody-positive rate of HIV[2019, 0.03% (17/54 110)], and there was a weak correlation on the antibody-positive rate of syphilis [2019, 0.08%(41/54 110)]. In 2019, the proportion of the respondents ever had sex was 8.71%(4 731/54 339), of those having regular sex partner in the last year was 3.96% (2 153/54 339), of those having a temporary partner was 1.81%(984/54 339), of a commercial sex partner was 0.19% (101/54 339), and of homosexual partners was 0.19% (101/54 339), who they were all stable. Multivariate logistic regression analysis showed that the young students who had male homosexual partners were most likely to be infected by HIV. The young students who had multiple sexual partners, including homosexual partners, were foreigners or minorities were most likely to be infected by syphilis (all P<0.05). Conclusions: The antibody-positive rates of HIV and syphilis remained low and stable among young students from 2015 to 2019 in China. However, the risk of sexual transmission of HIV and syphilis still remains among young students.

[Willingness on acceptance of peer-referral strategies for promoting HIV testing in men who have sex with men in Shijiazhuang]

Objective: To understand the willingness to accept peer-referral strategies for promoting HIV testing and related factors in men who have sex with men (MSM) in Shijiazhuang. Methods: A total of 544 MSM were recruited using convenient sampling and sharing two-dimensional code of online questionnaire througth MSM social organizations in Shijiazhuang from August to September in 2018. The anonymous online survey were taken by login through the website "jinshuju.com" (https://im.jinshuju.com/users/sign_in). The information collected included: the demographic and behavioral characteristics, the attitude to HIV testing for partners, and the willingness to accept peer-referral strategies for promoting HIV testing. The socio-demographic characteristics were analyzed by χ² test. Univariate and multivariate logistic regression analyses were conducted to identify the related factors associated with willingness. The SAS 9.4 software was used for statistical analysis. Results: A total of 521 MSM completed the survey. Among them 59.50% (310/521) were willing to advise their partners to receive HIV testing, and 90.02% (469/521) were willing to accept the partners' advice of HIV testing. Higher HIV testing frequency for once a year (aOR=2.72,95%CI:1.42-5.20); for once a half year (aOR=5.72, 95%CI:2.97-11.02); for ≥1 time a quarter (aOR=8.76,95%CI:4.56-16.83), enquiring their partners' HIV status (aOR=1.94, 95%CI: 1.15-3.28) and STD history of their partners (aOR=1.83, 95%CI:1.06-3.14) before having sex were the factors positively associated with the willingness to advise partners to receive HIV testing. Discussing HIV testing with partners (aOR=4.43,95%CI:1.87-10.54) was the factor positively associated with the desire to accept the advice of HIV testing from partners, but feeling emotional hurt by the suggestion of HIV testing (aOR=0.35,95%CI:0.15-0.82) was the factor negatively associated with the willingness to accept the advice of HIV testing from partners. Conclusion: To improve the willingess of MSM to advise their partners to receive HIV testing and strengthen self-protection awareness and equal communication skills are essential for the success of peer-referral strategies for promoting HIV testing among MSM.

Observation of a Near-Threshold Structure in the K^{+} Recoil-Mass Spectra in e^{+}e^{-}→K^{+}(D_{s}^{-}D^{*0}+D_{s}^{*-}D^{0})

We report a study of the processes of e^{+}e^{-}→K^{+}D_{s}^{-}D^{*0} and K^{+}D_{s}^{*-}D^{0} based on e^{+}e^{-} annihilation samples collected with the BESIII detector operating at BEPCII at five center-of-mass energies ranging from 4.628 to 4.698 GeV with a total integrated luminosity of 3.7  fb^{-1}. An excess of events over the known contributions of the conventional charmed mesons is observed near the D_{s}^{-}D^{*0} and D_{s}^{*-}D^{0} mass thresholds in the K^{+} recoil-mass spectrum for events collected at sqrt[s]=4.681  GeV. The structure matches a mass-dependent-width Breit-Wigner line shape, whose pole mass and width are determined as (3982.5_{-2.6}^{+1.8}±2.1)  MeV/c^{2} and (12.8_{-4.4}^{+5.3}±3.0)  MeV, respectively. The first uncertainties are statistical and the second are systematic. The significance of the resonance hypothesis is estimated to be 5.3  σ over the contributions only from the conventional charmed mesons. This is the first candidate for a charged hidden-charm tetraquark with strangeness, decaying into D_{s}^{-}D^{*0} and D_{s}^{*-}D^{0}. However, the properties of the excess need further exploration with more statistics.

Model-Independent Determination of the Spin of the Ω^{-} and Its Polarization Alignment in ψ(3686)→Ω^{-}Ω[over ¯]^{+}

We present an analysis of the process ψ(3686)→Ω^{-}Ω[over ¯]^{+} (Ω^{-}→K^{-}Λ, Ω[over ¯]^{+}→K^{+}Λ[over ¯], Λ→pπ^{-}, Λ[over ¯]→p[over ¯]π^{+}) based on a dataset of 448×10^{6}  ψ(3686) decays collected with the BESIII detector at the BEPCII electron-positron collider. The helicity amplitudes for the process ψ(3686)→Ω^{-}Ω[over ¯]^{+} and the decay parameters of the subsequent decay Ω^{-}→K^{-}Λ (Ω[over ¯]^{+}→K^{+}Λ[over ¯]) are measured for the first time by a fit to the angular distribution of the complete decay chain, and the spin of the Ω^{-} is determined to be 3/2 for the first time since its discovery more than 50 years ago.

[Estimation of newly HIV infection trend by using the back-calculation method in Honghe Hani and Yi autonomous prefecture]

Objective: Using the changing patterns of CD(4)(+) lymphocytes (CD(4)) counts of HIV/AIDS cases, we tried to estimate the number of newly infected HIV in Honghe Hani and Yi autonomous prefecture (Honghe prefecture) Yunnan province, and to provide reference for evaluating the trend of local HIV epidemic. Methods: Among diagnosed HIV infections, those who were at ≥15 years old, having available initial CD(4) records of testing, initiating antiviral therapy before the end of 2018, were selected from the case reporting system of Honghe prefecture, Yunnan province. Both Depletion model of the square root on CD(4) and the time of infection were used to back-calculate the seroconversion time of each individual. Both direct probability distribution method and life table method were used to calculate the distribution rates of diagnosis and the weight of delay. The number of diagnoses over the years was used to reversely estimate the total number of newly HIV infections. Results: At the end of 2018, the total number of HIV infections was estimated 35 977 with the rate of diagnosis as 77.50% in Honghe prefecture of Yunnan province. The number of new HIV infections appeared as 23 792 in 2008-2018. Cumulatively, the number of new HIV infections was 12 185 up to 2007. The estimated number of new HIV infections decreased from 2 602 in 2008 to 1 480 in 2018. The weight of diagnostic delay decreased from 5.49 in one year to 1.00 in 20 years, and the diagnosis rate increased from 18.2% to 100.0% during 20 years. Conclusion: In Honghe prefecture of Yunnan province, the number of newly infection showed a declining trend but the diagnostic rate was still far from reaching the "first 90% target" . It is expected to expand the timeliness on detection and case-finding so as to reduce the risk of HIV transmission.

[Progress of research on the susceptibility of HIV infection among heterosexual partners of men who have sex with men]

Affected by internal and external factors, more than 70.0% of men who have sex with men (MSM) have the intention to get married, and more than 90.0% of MSM view marriage as inevitable. Due to the marriage, there merges a group of women who are heterosexual partners of MSM and also known as'tongqi' (TQ). Because MSM is a high-risk group infected with HIV, together with the existence of other predisposing factors, the TQ population is also under increased risk of HIV infection. This article summarizes the definition, population scale, physical health problems, and risk factors of HIV infection among TQ with the purpose of providing evidence for the implementation on the follow-up prevention and control programs of sexually transmitted diseases for the TQ population.

Observation of the Doubly Cabibbo-Suppressed Decay D^{+}→K^{+}π^{+}π^{-}π^{0} and Evidence for D^{+}→K^{+}ω

Using 2.93  fb^{-1} of e^{+}e^{-} collision data collected at a center-of-mass energy of 3.773 GeV with the BESIII detector, the first observation of the doubly Cabibbo-suppressed decay D^{+}→K^{+}π^{+}π^{-}π^{0} is reported. After removing decays that contain narrow intermediate resonances, including D^{+}→K^{+}η, D^{+}→K^{+}ω, and D^{+}→K^{+}ϕ, the branching fraction of the decay D^{+}→K^{+}π^{+}π^{-}π^{0} is measured to be (1.13±0.08_{stat}±0.03_{syst})×10^{-3}. The ratio of branching fractions of D^{+}→K^{+}π^{+}π^{-}π^{0} over D^{+}→K^{-}π^{+}π^{+}π^{0} is found to be (1.81±0.15)%, which corresponds to (6.28±0.52)tan^{4}θ_{C}, where θ_{C} is the Cabibbo mixing angle. This ratio is significantly larger than the corresponding ratios for other doubly Cabibbo-suppressed decays. The asymmetry of the branching fractions of charge-conjugated decays D^{±}→K^{±}π^{±}π^{∓}π^{0} is also determined, and no evidence for CP violation is found. In addition, the first evidence for the D^{+}→K^{+}ω decay, with a statistical significance of 3.3σ, is presented and the branching fraction is measured to be B(D^{+}→K^{+}ω)=(5.7_{-2.1}^{+2.5}_{stat}±0.2_{syst})×10^{-5}.

Σ^{+} and Σ[over ¯]^{-} Polarization in the J/ψ and ψ(3686) Decays

From 1310.6×10^{6}  J/ψ and 448.1×10^{6}  ψ(3686) events collected with the BESIII experiment, we report the first observation of Σ^{+} and Σ[over ¯]^{-} spin polarization in e^{+}e^{-}→J/ψ[ψ(3686)]→Σ^{+}Σ[over ¯]^{-} decays. The relative phases of the form factors ΔΦ have been measured to be (-15.5±0.7±0.5)° and (21.7±4.0±0.8)° with J/ψ and ψ(3686) data, respectively. The nonzero value of ΔΦ allows for a direct and simultaneous measurement of the decay asymmetry parameters of Σ^{+}→pπ^{0}(α_{0}=-0.998±0.037±0.009) and Σ[over ¯]^{-}→p[over ¯]π^{0}(α[over ¯]_{0}=0.990±0.037±0.011), the latter value being determined for the first time. The average decay asymmetry, (α_{0}-α[over ¯]_{0})/2, is calculated to be -0.994±0.004±0.002. The CP asymmetry A_{CP,Σ}=(α_{0}+α[over ¯]_{0})/(α_{0}-α[over ¯]_{0})=-0.004±0.037±0.010 is extracted for the first time, and is found to be consistent with CP conservation.

Study of Open-Charm Decays and Radiative Transitions of the X(3872)

The processes X(3872)→D^{*0}D[over ¯]^{0}+c.c.,γJ/ψ,γψ(2S), and γD^{+}D^{-} are searched for in a 9.0  fb^{-1} data sample collected at center-of-mass energies between 4.178 and 4.278 GeV with the BESIII detector. We observe X(3872)→D^{*0}D^{0}[over ¯]+c.c. and find evidence for X(3872)→γJ/ψ with statistical significances of 7.4σ and 3.5σ, respectively. No evident signals for X(3872)→γψ(2S) and γD^{+}D^{-} are found, and the upper limit on the relative branching ratio R_{γψ}≡{B[X(3872)→γψ(2S)]}/{B[X(3872)→γJ/ψ]}<0.59 is set at 90% confidence level. Measurements of branching ratios relative to decay X(3872)→π^{+}π^{-}J/ψ are also reported for decays X(3872)→D^{*0}D^{0}[over ¯]+c.c.,γψ(2S),γJ/ψ, and γD^{+}D^{-}, as well as the non-D^{*0}D^{0}[over ¯] three-body decays π^{0}D^{0}D^{0}[over ¯] and γD^{0}D^{0}[over ¯].

Measurements of Absolute Branching Fractions of Fourteen Exclusive Hadronic D Decays to η

Using 2.93  fb^{-1} of e^{+}e^{-} collision data taken at a center-of-mass energy of 3.773 GeV with the BESIII detector, we report the first measurements of the absolute branching fractions of 14 hadronic D^{0(+)} decays to exclusive final states with an η, e.g., D^{0}→K^{-}π^{+}η, K_{S}^{0}π^{0}η, K^{+}K^{-}η, K_{S}^{0}K_{S}^{0}η, K^{-}π^{+}π^{0}η, K_{S}^{0}π^{+}π^{-}η, K_{S}^{0}π^{0}π^{0}η, and π^{+}π^{-}π^{0}η; D^{+}→K_{S}^{0}π^{+}η, K_{S}^{0}K^{+}η, K^{-}π^{+}π^{+}η, K_{S}^{0}π^{+}π^{0}η, π^{+}π^{+}π^{-}η, and π^{+}π^{0}π^{0}η. Among these decays, the D^{0}→K^{-}π^{+}η and D^{+}→K_{S}^{0}π^{+}η decays have the largest branching fractions, which are B(D^{0}→K^{-}π^{+}η)=(1.853±0.025_{stat}±0.031_{syst})% and B(D^{+}→K_{S}^{0}π^{+}η)=(1.309±0.037_{stat}±0.031_{syst})%, respectively. The charge-parity asymmetries for the six decays with highest event yields are determined, and no statistically significant charge-parity violation is found.

Determination of Strong-Phase Parameters in D→K_{S,L}^{0}π^{+}π^{-}

We report the most precise measurements to date of the strong-phase parameters between D^{0} and D[over ¯]^{0} decays to K_{S,L}^{0}π^{+}π^{-} using a sample of 2.93  fb^{-1} of e^{+}e^{-} annihilation data collected at a center-of-mass energy of 3.773 GeV with the BESIII detector at the BEPCII collider. Our results provide the key inputs for a binned model-independent determination of the Cabibbo-Kobayashi-Maskawa angle γ/ϕ_{3} with B decays. Using our results, the decay model sensitivity to the γ/ϕ_{3} measurement is expected to be between 0.7° and 1.2°, approximately a factor of three smaller than that achievable with previous measurements, based on the studies of the simulated data. The improved precision of this work ensures that measurements of γ/ϕ_{3} will not be limited by knowledge of strong phases for the next decade. Furthermore, our results provide critical input for other flavor-physics investigations, including charm mixing, other measurements of CP violation, and the measurement of strong-phase parameters for other D-decay modes.

First Observation of D^{+}→ημ^{+}ν_{μ} and Measurement of Its Decay Dynamics

By analyzing a data sample corresponding to an integrated luminosity of 2.93  fb^{-1} collected at a center-of-mass energy of 3.773 GeV with the BESIII detector, we measure for the first time the absolute branching fraction of the D^{+}→ημ^{+}ν_{μ} decay to be B_{D^{+}→ημ^{+}ν_{μ}}=(10.4±1.0_{stat}±0.5_{syst})×10^{-4}. Using the world averaged value of B_{D^{+}→ηe^{+}ν_{e}}, the ratio of the two branching fractions is determined to be B_{D^{+}→ημ^{+}ν_{μ}}/B_{D^{+}→ηe^{+}ν_{e}}=0.91±0.13_{(stat+syst)}, which agrees with the theoretical expectation of lepton flavor universality within uncertainty. By studying the differential decay rates in five four-momentum transfer intervals, we obtain the product of the hadronic form factor f_{+}^{η}(0) and the c→d Cabibbo-Kobayashi-Maskawa matrix element |V_{cd}| to be f_{+}^{η}(0)|V_{cd}|=0.087±0.008_{stat}±0.002_{syst}. Taking the input of |V_{cd}| from the global fit in the standard model, we determine f_{+}^{η}(0)=0.39±0.04_{stat}±0.01_{syst}. On the other hand, using the value of f_{+}^{η}(0) calculated in theory, we find |V_{cd}|=0.242±0.022_{stat}±0.006_{syst}±0.033_{theory}.

First Observation of D^{+}→ημ^{+}ν_{μ} and Measurement of Its Decay Dynamics

By analyzing a data sample corresponding to an integrated luminosity of 2.93  fb^{-1} collected at a center-of-mass energy of 3.773 GeV with the BESIII detector, we measure for the first time the absolute branching fraction of the D^{+}→ημ^{+}ν_{μ} decay to be B_{D^{+}→ημ^{+}ν_{μ}}=(10.4±1.0_{stat}±0.5_{syst})×10^{-4}. Using the world averaged value of B_{D^{+}→ηe^{+}ν_{e}}, the ratio of the two branching fractions is determined to be B_{D^{+}→ημ^{+}ν_{μ}}/B_{D^{+}→ηe^{+}ν_{e}}=0.91±0.13_{(stat+syst)}, which agrees with the theoretical expectation of lepton flavor universality within uncertainty. By studying the differential decay rates in five four-momentum transfer intervals, we obtain the product of the hadronic form factor f_{+}^{η}(0) and the c→d Cabibbo-Kobayashi-Maskawa matrix element |V_{cd}| to be f_{+}^{η}(0)|V_{cd}|=0.087±0.008_{stat}±0.002_{syst}. Taking the input of |V_{cd}| from the global fit in the standard model, we determine f_{+}^{η}(0)=0.39±0.04_{stat}±0.01_{syst}. On the other hand, using the value of f_{+}^{η}(0) calculated in theory, we find |V_{cd}|=0.242±0.022_{stat}±0.006_{syst}±0.033_{theory}.

Observation of a Resonant Structure in e^{+}e^{-}→K^{+}K^{-}π^{0}π^{0}

A partial-wave analysis is performed for the process e^{+}e^{-}→K^{+}K^{-}π^{0}π^{0} at the center-of-mass energies ranging from 2.000 to 2.644 GeV. The data samples of e^{+}e^{-} collisions, collected by the BESIII detector at the BEPCII collider with a total integrated luminosity of 300  pb^{-1}, are analyzed. The total Born cross sections for the process e^{+}e^{-}→K^{+}K^{-}π^{0}π^{0}, as well as the Born cross sections for the subprocesses e^{+}e^{-}→ϕπ^{0}π^{0}, K^{+}(1460)K^{-}, K_{1}^{+}(1400)K^{-}, K_{1}^{+}(1270)K^{-}, and K^{*+}(892)K^{*-}(892), are measured versus the center-of-mass energy. The corresponding results for e^{+}e^{-}→K^{+}K^{-}π^{0}π^{0} and ϕπ^{0}π^{0} are consistent with those of BABAR with better precision. By analyzing the cross sections for the four subprocesses, K^{+}(1460)K^{-}, K_{1}^{+}(1400)K^{-}, K_{1}^{+}(1270)K^{-}, and K^{*+}(892)K^{*-}(892), a structure with mass M=(2126.5±16.8±12.4)  MeV/c^{2} and width Γ=(106.9±32.1±28.1)  MeV is observed with an overall statistical significance of 6.3σ, although with very limited significance in the subprocesses e^{+}e^{-}→K_{1}^{+}(1270)K^{-} and K^{*+}(892)K^{*-}(892). The resonant parameters of the observed structure suggest it can be identified with the ϕ(2170), thus the results provide valuable input to the internal nature of the ϕ(2170).

Measurement of Proton Electromagnetic Form Factors in e^{+}e^{-}→pp[over ¯] in the Energy Region 2.00-3.08 GeV

The process of e^{+}e^{-}→pp[over ¯] is studied at 22 center-of-mass energy points (sqrt[s]) from 2.00 to 3.08 GeV, exploiting 688.5  pb^{-1} of data collected with the BESIII detector operating at the BEPCII collider. The Born cross section (σ_{pp[over ¯]}) of e^{+}e^{-}→pp[over ¯] is measured with the energy-scan technique and it is found to be consistent with previously published data, but with much improved accuracy. In addition, the electromagnetic form-factor ratio (|G_{E}/G_{M}|) and the value of the effective (|G_{eff}|), electric (|G_{E}|), and magnetic (|G_{M}|) form factors are measured by studying the helicity angle of the proton at 16 center-of-mass energy points. |G_{E}/G_{M}| and |G_{M}| are determined with high accuracy, providing uncertainties comparable to data in the spacelike region, and |G_{E}| is measured for the first time. We reach unprecedented accuracy, and precision results in the timelike region provide information to improve our understanding of the proton inner structure and to test theoretical models which depend on nonperturbative quantum chromodynamics.

Measurement of the Cross Section for e^{+}e^{-}→Ξ^{-}Ξ[over ¯]^{+} and Observation of an Excited Ξ Baryon

Using a total of 11.0  fb^{-1} of e^{+}e^{-} collision data with center-of-mass energies between 4.009 and 4.6 GeV and collected with the BESIII detector at BEPCII, we measure fifteen exclusive cross sections and effective form factors for the process e^{+}e^{-}→Ξ^{-}Ξ[over ¯]^{+} by means of a single baryon-tag method. After performing a fit to the dressed cross section of e^{+}e^{-}→Ξ^{-}Ξ[over ¯]^{+}, no significant ψ(4230) or ψ(4260) resonance is observed in the Ξ^{-}Ξ[over ¯]^{+} final states, and upper limits at the 90% confidence level on Γ_{ee}B for the processes ψ(4230)/ψ(4260)→Ξ^{-}Ξ[over ¯]^{+} are determined. In addition, an excited Ξ baryon at 1820  MeV/c^{2} is observed with a statistical significance of 6.2-6.5σ by including the systematic uncertainty, and the mass and width are measured to be M=(1825.5±4.7±4.7)  MeV/c^{2} and Γ=(17.0±15.0±7.9)  MeV, which confirms the existence of the J^{P}=3/2^{-} state Ξ(1820).

Observation of the Semileptonic D^{+} Decay into the K[over ¯]_{1}(1270)^{0} Axial-Vector Meson

By analyzing a 2.93  fb^{-1} data sample of e^{+}e^{-} collisions, recorded at a center-of-mass energy of 3.773 GeV with the BESIII detector operated at the BEPCII collider, we report the first observation of the semileptonic D^{+} transition into the axial-vector meson D^{+}→K[over ¯]_{1}(1270)^{0}e^{+}ν_{e} with a statistical significance greater than 10σ. Its decay branching fraction is determined to be B[D^{+}→K[over ¯]_{1}(1270)^{0}e^{+}ν_{e}]=(2.30±0.26_{-0.21}^{+0.18}±0.25)×10^{-3}, where the first and second uncertainties are statistical and systematic, respectively, and the third originates from the input branching fraction of K[over ¯]_{1}(1270)^{0}→K^{-}π^{+}π^{0}.

Observation of the Leptonic Decay D^{+}→τ^{+}ν_{τ}

We report the first observation of D^{+}→τ^{+}ν_{τ} with a significance of 5.1σ. We measure B(D^{+}→τ^{+}ν_{τ})=(1.20±0.24_{stat}±0.12_{syst})×10^{-3}. Taking the world average B(D^{+}→μ^{+}ν_{μ})=(3.74±0.17)×10^{-4}, we obtain R_{τ/μ}=Γ(D^{+}→τ^{+}ν_{τ})/Γ(D^{+}→μ^{+}ν_{μ})=3.21±0.64_{stat}±0.43_{syst}., which is consistent with the standard model expectation of lepton flavor universality. Using external inputs, our results give values for the D^{+} decay constant f_{D^{+}} and the Cabibbo-Kobayashi-Maskawa matrix element |V_{cd}| that are consistent with, but less precise than, other determinations.

Complete Measurement of the Λ Electromagnetic Form Factors

The exclusive process e^{+}e^{-}→ΛΛ[over ¯], with Λ→pπ^{-} and Λ[over ¯]→p[over ¯]π^{+}, has been studied at sqrt[s]=2.396  GeV for measurement of the timelike Λ electric and magnetic form factors, G_{E} and G_{M}. A data sample, corresponding to an integrated luminosity of 66.9  pb^{-1}, was collected with the BESIII detector for this purpose. A multidimensional analysis with a complete decomposition of the spin structure of the reaction enables a determination of the modulus of the ratio R=|G_{E}/G_{M}| and, for the first time for any baryon, the relative phase ΔΦ=Φ_{E}-Φ_{M}. The resulting values are R=0.96±0.14(stat)±0.02(syst) and ΔΦ=37°±12°(stat)±6°(syst), respectively. These are obtained using the recently established and most precise value of the asymmetry parameter α_{Λ}=0.750±0.010 measured by BESIII. In addition, the cross section is measured with unprecedented precision to be σ=118.7±5.3(stat)±5.1(syst)  pb, which corresponds to an effective form factor of |G|=0.123±0.003(stat)±0.003(syst). The contribution from two-photon exchange is found to be negligible. Our result enables the first complete determination of baryon timelike electromagnetic form factors.

Amplitude Analysis of D_{s}^{+}→π^{+}π^{0}η and First Observation of the W-Annihilation Dominant Decays D_{s}^{+}→a_{0}(980)^{+}π^{0} and D_{s}^{+}→a_{0}(980)^{0}π^{+}

We present the first amplitude analysis of the decay D_{s}^{+}→π^{+}π^{0}η. We use an e^{+}e^{-} collision data sample corresponding to an integrated luminosity of 3.19  fb^{-1} collected with the BESIII detector at a center-of-mass energy of 4.178 GeV. We observe for the first time the W-annihilation dominant decays D_{s}^{+}→a_{0}(980)^{+}π^{0} and D_{s}^{+}→a_{0}(980)^{0}π^{+}. We measure the absolute branching fraction B(D_{s}^{+}→a_{0}(980)^{+(0)}π^{0^{(}+)},a_{0}(980)^{+(0)}→π^{+(0)}η)=(1.46±0.15_{stat}±0.23_{sys})%, which is larger than the branching fractions of other measured pure W-annihilation decays by at least one order of magnitude. In addition, we measure the branching fraction of D_{s}^{+}→π^{+}π^{0}η with significantly improved precision.

[The hybridization and integration in the treatment of cerebral vascular diseases]

Multi-modalities integration is important in improving the outcome of patients with neurovascular diseases.Based on hybrid operation, this mode also integrates modern intraoperative image and monitoring techniques such as neuronavigation and intraoperative electrophysiological monitoring, providing safe, effective and cost-efficient therapies to certain diseases with the cooperation of neurosurgery and neurology department, which has been becoming the direction of modern individualized precise neurosurgery development.

[Analysis on condom use negotiation with sex partners and condom use in female sex workers]

Objective: To know condom use negotiation with clients and regular sex partners and condom use in female sex workers (FSWs), and provide reference for the development of comprehensive HIV/AIDS intervention for FSWs. Methods: The cross sectional survey was conducted in Jianshui county and Mengzi county in Honghe Hani and Yi autonomous prefecture. A total of 476 FSWs aged 16 years and above were recruited from entertainment venues, and the information about their demographic characteristics, condom use negotiation and condom use were collected by using questionnaires. Logistic regression model was used to analyze related factors of condom use after negotiation between FSWs and clients unwilling use condom. Results: A total of 852 FSWs who aged (24.29±8.44) years old participated in the survey. In past month, 499 FSWs had negotiation for condom use with unwilling clients (58.6%, 499/852), after negotiation, 441 FSWs (88.4%, 441/499) had consistent condom use in each sex with the clients. In the past one month, 99 FSWs had negotiation for unwilling use condom with regular sex partners (14.4%, 99/687), after negotiation, 54 FSWs (54.5%, 54/99) had consistent condom use in each sex with regular sex partners. Among the FSWs, 266 (53.3%, 266/499) reported that they could say "It is a mandatory requirement" to persuade clients who were unwilling to use condom. 97(19.4%, 97/499) reported that they could say "There is risk for infection" to persuade clients who were unwilling to use condoms. 115 (23.1%,115/499) reported that they could say "It is a mandatory requirement" and "there is risk for infection" to persuade their unwilling clients to use condoms. 21 (4.2%, 21/499) reported that they used other strategies. 22 (4.4%, 22/499) felt that it was difficult to persuade clients to use condoms. Multivariate logistic regression analysis showed that compared with FSWs who felt difficult in persuading clients to use condoms, FSWs who felt moderate difficulty were more likely to have consistent condom use after negotiation (OR=4.00, 95%CI: 1.55-10.32) and FSWs who felt easy in persuading clients to use condoms were also more likely to have consistent condom use (OR=30.17, 95%CI: 3.22-282.44). Compared with FSWs used other strategies to persuade their clients to use condoms, FSWs who said it was a mandatory requirement were more likely to have consistent condom use after negotiation (OR=4.44, 95%CI: 1.41-14.01) and FSWs who said it was a mandatory requirement and there was risk for infection were also more likely to have consistent condom use (OR=5.52, 95%CI: 1.55-19.73). Conclusions: Negotiation for condom use increased the rate of condom use in FSWs in sex with clients who were unwilling to use condom. The negotiation strategy of "It is a mandatory requirement" would promote condom use in FSWs in sex with clients who were unwilling to use condom. Besides, the negotiation strategy of saying "there is risk for infection" had additional effects.

Study of e^{+}e^{-}→γωJ/ψ and Observation of X(3872)→ωJ/ψ

We study the e^{+}e^{-}→γωJ/ψ process using 11.6  fb^{-1} e^{+}e^{-} annihilation data taken at center-of-mass energies from sqrt[s]=4.008  GeV to 4.600 GeV with the BESIII detector at the BEPCII storage ring. The X(3872) resonance is observed for the first time in the ωJ/ψ system with a significance of more than 5σ. The relative decay ratio of X(3872)→ωJ/ψ and π^{+}π^{-}J/ψ is measured to be R=1.6_{-0.3}^{+0.4}±0.2, where the first uncertainty is statistical and the second systematic (the same hereafter). The sqrt[s]-dependent cross section of e^{+}e^{-}→γX(3872) is also measured and investigated, and it can be described by a single Breit-Wigner resonance, referred to as the Y(4200), with a mass of 4200.6_{-13.3}^{+7.9}±3.0  MeV/c^{2} and a width of 115_{-26}^{+38}±12  MeV. In addition, to describe the ωJ/ψ mass distribution above 3.9  GeV/c^{2}, we need at least one additional Breit-Wigner resonance, labeled as X(3915), in the fit. The mass and width of the X(3915) are determined. The resonant parameters of the X(3915) agree with those of the Y(3940) in B→KωJ/ψ and of the X(3915) in γγ→ωJ/ψ observed by the Belle and BABAR experiments within errors.

Observation of the Decay X(3872)→π^{0}χ_{c1}(1P)

Using a total of 9.0  fb^{-1} of e^{+}e^{-} collision data with center-of-mass energies between 4.15 and 4.30 GeV collected by the BESIII detector, we search for the processes e^{+}e^{-}→γX(3872) with X(3872)→π^{0}χ_{cJ} for J=0, 1, 2. We report the first observation of X(3872)→π^{0}χ_{c1}, a new decay mode of the X(3872), with a statistical significance of more than 5σ for all systematic fit variations. Normalizing to the previously established process e^{+}e^{-}→γX(3872) with X(3872)→π^{+}π^{-}J/ψ, we find B(X(3872)→π^{0}χ_{c1})/B(X(3872)→π^{+}π^{-}J/ψ)=0.88_{-0.27}^{+0.33}±0.10, where the first error is statistical and the second is systematic. We set 90% confidence level upper limits on the corresponding ratios for the decays to π^{0}χ_{c0} and π^{0}χ_{c2} of 19 and 1.1, respectively.

Precision Measurement of the Branching Fractions of η^{'} Decays

Based on a sample of (1310.6±7.0)×10^{6}J/ψ events collected with the BESIII detector, we present measurements of J/ψ and η^{'} absolute branching fractions using the process J/ψ→γη^{'}. By analyzing events where the radiative photon converts into an e^{+}e^{-} pair, the branching fraction for J/ψ→γη^{'} is measured to be (5.27±0.03±0.05)×10^{-3}. The absolute branching fractions of the five dominant decay channels of the η^{'} are then measured for the first time and are determined to be B(η^{'}→γπ^{+}π^{-})=(29.90±0.03±0.55)%, B(η^{'}→ηπ^{+}π^{-})=(41.24±0.08±1.24)%, B(η^{'}→ηπ^{0}π^{0})=(21.36±0.10±0.92)%, B(η^{'}→γω)=(2.489±0.018±0.074)%, and B(η^{'}→γγ)=(2.331±0.012±0.035)%, where the first uncertainties are statistical and the second systematic.

Measurement of the Dynamics of the Decays D_{s}^{+}→η^{(')}e^{+}ν_{e}

Using e^{+}e^{-} annihilation data corresponding to an integrated luminosity of 3.19  fb^{-1} collected at a center-of-mass energy of 4.178 GeV with the BESIII detector, we measure the absolute branching fractions B_{D_{s}^{+}→ηe^{+}ν_{e}}=(2.323±0.063_{stat}±0.063_{syst})% and B_{D_{s}^{+}→η^{'}e^{+}ν_{e}}=(0.824±0.073_{stat}±0.027_{syst})% via a tagged analysis technique, where one D_{s} is fully reconstructed in a hadronic mode. Combining these measurements with previous BESIII measurements of B_{D^{+}→η^{(')}e^{+}ν_{e}}, the η-η^{'} mixing angle in the quark flavor basis is determined to be ϕ_{P}=(40.1±2.1_{stat}±0.7_{syst})°. From the first measurements of the dynamics of D_{s}^{+}→η^{(')}e^{+}ν_{e} decays, the products of the hadronic form factors f_{+}^{η^{(')}}(0) and the Cabibbo-Kobayashi-Maskawa matrix element |V_{cs}| are determined with different form factor parametrizations. For the two-parameter series expansion, the results are f_{+}^{η}(0)|V_{cs}|=0.4455±0.0053_{stat}±0.0044_{syst} and f_{+}^{η^{'}}(0)|V_{cs}|=0.477±0.049_{stat}±0.011_{syst}.

Evidence of a Resonant Structure in the e^{+}e^{-}→π^{+}D^{0}D^{*-} Cross Section between 4.05 and 4.60 GeV

The cross section of the process e^{+}e^{-}→π^{+}D^{0}D^{*-} for center-of-mass energies from 4.05 to 4.60 GeV is measured precisely using data samples collected with the BESIII detector operating at the BEPCII storage ring. Two enhancements are clearly visible in the cross section around 4.23 and 4.40 GeV. Using several models to describe the dressed cross section yields stable parameters for the first enhancement, which has a mass of 4228.6±4.1±6.3  MeV/c^{2} and a width of 77.0±6.8±6.3  MeV, where the first uncertainties are statistical and the second ones are systematic. Our resonant mass is consistent with previous observations of the Y(4220) state and the theoretical prediction of a DD[over ¯]_{1}(2420) molecule. This result is the first observation of Y(4220) associated with an open-charm final state. Fits with three resonance functions with additional Y(4260), Y(4320), Y(4360), ψ(4415), or a new resonance do not show significant contributions from either of these resonances. The second enhancement is not from a single known resonance. It could contain contributions from ψ(4415) and other resonances, and a detailed amplitude analysis is required to better understand this enhancement.

[Differences of brain functional alterations between subtypes of Cushing's syndrome patients]

Objective: To compare the differences of brain functional damage of subtypes of patients with Cushing's syndrome (CS). Methods: A total of 11 adrenocorticotropic hormone (ACTH)-dependent CS patients and 29 ACTH-independent CS patients were recruited from Chinese PLA General Hospital between September 2015 and March 2017 with confirmed CS. The psychiatric scales and brain task functional magnetic resonance imaging (fMRI) were evaluated. Results: A total of 40 patients (34 females, 6 males) with a mean age of (39.20±12.10) years and a median education level of 12 (9, 16) years were enrolled. ACTH-dependent patients had significantly worse performance than the ACTH-independent patients in response to the depression evaluation (64.6±6.1 vs 56.2±12.8, P=0.008), positive emotion (17.8±4.2 vs 24.3±7.2, P=0.008) and CS life quality [31(29,33) vs 42(29,51), P=0.040]. In the reaction to positive target pictures, ACTH-dependent CS patients showed stronger activation in left superior temporal gyrus compared with patients in ACTH-independent group, while the activation degree of their bilateral dorsal anterior cingulate cortex, bilateralsuperior frontal gyrus and left middle frontal gyrus was much worse. In the reactions to negative target pictures, ACTH-dependent CS patients had weaker activation in bilateral cerebellum, left superior frontal gyrus, left middle frontal gyrus, left precuneus and right postcentral gyrus, compared with patients in the ACTH-independent CS group (P<0.01, AlphaSim corrected). The activation degree of some regions whose brain function was different between the two groups was correlated to the cortisol level, ACTH level, 24 h urinary free cortisol (UFC) level, depression evaluation and negative emotion assessment (all P<0.05). Conclusions: The severity of the depression and the life quality of patients in ACTH-dependent group are worse than ACTH-independent CS patients. The brain function of ACTH-dependent CS patients is much weaker.

Determination of the Pseudoscalar Decay Constant f_{D_{s}^{+}} via D_{s}^{+}→μ^{+}ν_{μ}

Using a 3.19  fb^{-1} data sample collected at an e^{+}e^{-} center-of-mass energy of E_{cm}=4.178  GeV with the BESIII detector, we measure the branching fraction of the leptonic decay D_{s}^{+}→μ^{+}ν_{μ} to be B_{D_{s}^{+}→μ^{+}ν_{μ}}=(5.49±0.16_{stat}±0.15_{syst})×10^{-3}. Combining our branching fraction with the masses of the D_{s}^{+} and μ^{+} and the lifetime of the D_{s}^{+}, we determine f_{D_{s}^{+}}|V_{cs}|=246.2±3.6_{stat}±3.5_{syst}  MeV. Using the c→s quark mixing matrix element |V_{cs}| determined from a global standard model fit, we evaluate the D_{s}^{+} decay constant f_{D_{s}^{+}}=252.9±3.7_{stat}±3.6_{syst}  MeV. Alternatively, using the value of f_{D_{s}^{+}} calculated by lattice quantum chromodynamics, we find |V_{cs}|=0.985±0.014_{stat}±0.014_{syst}. These values of B_{D_{s}^{+}→μ^{+}ν_{μ}}, f_{D_{s}^{+}}|V_{cs}|, f_{D_{s}^{+}} and |V_{cs}| are each the most precise results to date.

First Measurement of the Form Factors in D_{s}^{+}→K^{0}e^{+}ν_{e} and D_{s}^{+}→K^{*0}e^{+}ν_{e} Decays

We report on new measurements of Cabibbo-suppressed semileptonic D_{s}^{+} decays using 3.19  fb^{-1} of e^{+}e^{-} annihilation data sample collected at a center-of-mass energy of 4.178 GeV with the BESIII detector at the BEPCII collider. Our results include branching fractions B(D_{s}^{+}→K^{0}e^{+}ν_{e})=[3.25±0.38(stat)±0.16(syst)]×10^{-3} and B(D_{s}^{+}→K^{*0}e^{+}ν_{e})=[2.37±0.26(stat)±0.20(syst)]×10^{-3}, which are much improved relative to previous measurements, and the first measurements of the hadronic form-factor parameters for these decays. For D_{s}^{+}→K^{0}e^{+}ν_{e}, we obtain f_{+}(0)=0.720±0.084(stat)±0.013(syst), and for D_{s}^{+}→K^{*0}e^{+}ν_{e}, we find form-factor ratios r_{V}=V(0)/A_{1}(0)=1.67±0.34(stat)±0.16(syst) and r_{2}=A_{2}(0)/A_{1}(0)=0.77±0.28(stat)±0.07(syst).

Observation of D^{+}→f_{0}(500)e^{+}ν_{e} and Improved Measurements of D→ρe^{+}ν_{e}

Using a data sample corresponding to an integrated luminosity of 2.93  fb^{-1} recorded by the BESIII detector at a center-of-mass energy of 3.773 GeV, we present an analysis of the decays D^{0}→π^{-}π^{0}e^{+}ν_{e} and D^{+}→π^{-}π^{+}e^{+}ν_{e}. By performing a partial wave analysis, the π^{+}π^{-} S-wave contribution to D^{+}→π^{-}π^{+}e^{+}ν_{e} is observed to be (25.7±1.6±1.1)% with a statistical significance greater than 10σ, besides the dominant P-wave contribution. This is the first observation of the S-wave contribution. We measure the branching fractions B(D^{0}→ρ^{-}e^{+}ν_{e})=(1.445±0.058±0.039)×10^{-3}, B(D^{+}→ρ^{0}e^{+}ν_{e})=(1.860±0.070±0.061)×10^{-3}, and B(D^{+}→f_{0}(500)e^{+}ν_{e},f_{0}(500)→π^{+}π^{-})=(6.30±0.43±0.32)×10^{-4}. An upper limit of B(D^{+}→f_{0}(980)e^{+}ν_{e},f_{0}(980)→π^{+}π^{-})<2.8×10^{-5} is set at the 90% confidence level. We also obtain the hadronic form factor ratios of D→ρe^{+}ν_{e} at q^{2}=0 assuming the single-pole dominance parametrization: r_{V}={[V(0)]/[A_{1}(0)]}=1.695±0.083±0.051, r_{2}={[A_{2}(0)]/[A_{1}(0)]}=0.845±0.056±0.039.

Study of the D^{0}→K^{-}μ^{+}ν_{μ} Dynamics and Test of Lepton Flavor Universality with D^{0}→K^{-}ℓ^{+}ν_{ℓ} Decays

Using e^{+}e^{-} annihilation data of 2.93  fb^{-1} collected at center-of-mass energy sqrt[s]=3.773  GeV with the BESIII detector, we measure the absolute branching fraction of D^{0}→K^{-}μ^{+}ν_{μ} with significantly improved precision: B_{D^{0}→K^{-}μ^{+}ν_{μ}}=(3.413±0.019_{stat}±0.035_{syst})%. Combining with our previous measurement of B_{D^{0}→K^{-}e^{+}ν_{e}}, the ratio of the two branching fractions is determined to be B_{D^{0}→K^{-}μ^{+}ν_{μ}}/B_{D^{0}→K^{-}e^{+}ν_{e}}=0.974±0.007_{stat}±0.012_{syst}, which agrees with the theoretical expectation of lepton flavor universality within the uncertainty. A study of the ratio of the two branching fractions in different four-momentum transfer regions is also performed, and no evidence for lepton flavor universality violation is found with current statistics. Taking inputs from global fit in the standard model and lattice quantum chromodynamics separately, we determine f_{+}^{K}(0)=0.7327±0.0039_{stat}±0.0030_{syst} and |V_{cs}|=0.955±0.005_{stat}±0.004_{syst}±0.024_{LQCD}.

[Study on the prevalence of HIV infection and related risk behaviors among male new-type drug users in Qingdao, Shandong province]

Objective: To understand the characteristics of new-type drug consumption, sexual behaviors and the prevalence of HIV infection among male new-type drug users in Qingdao, Shandong province. Methods: A cross sectional survey was conducted from 2015 to 2016. Participants were recruited from MSM community-based organizations (CBO) and general community through snowball method, relying on volunteers and male peer educators who were on new-type drugs themselves. Face-to-face interview was carried to collect information on drug use and sexual behaviors. Blood samples were collected to test HIV, syphilis and HCV antibodies. Urine samples were collected to test the evidence of new-type drugs. Qualitative variables and quantitative variables were analyzed using Chi-square test/Fisher's exact test and Student's t-test respectively. Multivariate logistic regression was used to analyze related factors of binary variables. Results: A total of 1 034 newtype drug users were recruited, including 431 (41.7%) MSM population and 603 (58.3%) who were not MSM. Compared with the the group of people who were not MSM, people in the the MSM group were younger, unmarried and with higher level of education. The proportion of methamphetamine users were 49.7% (214/431) and 100.0% (603/603) among the groups of MSM or not MSM, respectively. People in the MSM group, 66.8% (288/431) used 5-Methoxy-N, N-diisopropyltryptamine (5-MeODIPT, "foxy" ) in the last six months. However, none from the not-MSM group ever used 5-MeO-DIPT. In the last six months, proportions of sharing new-type drugs with more than two people in the MSM or not groups were 87.9% (379/431) and 97.7% (588/602), respectively (χ(2)=39.84, P<0.01). Proportions of unprotected sexual behavior among the MSM or not groups were 47.5% (285/600) and 7.4% (32/430) respectively (χ(2)=190.10, P<0.01). The proportions of 'group sex' after using drugs among the two groups were 78.1% (335/429) and 5.5% (33/600) respectively (χ(2)=573.73, P<0.01). The prevalence rates of HIV, syphilis and HCV antibody positive among the MSM or not groups were 2.1% and 0.2%, 3.3% and 6.3%, 0.0% and 0.3%, respectively. Conclusion: The prevalence of sharing new-type drugs with more than two people was high among male new-type drug users in Qingdao city. Male new-type-drug-users who were MSM, presented both high prevalence of group sex and HIV infection, and with less condom use. Intervention measures towards this sub-population should be strengthened.

Measurement of the Absolute Branching Fraction of the Inclusive Semileptonic Λ_{c}^{+} Decay

Using a data sample of e^{+}e^{-} collisions corresponding to an integrated luminosity of 567  pb^{-1} collected at a center-of-mass energy of sqrt[s]=4.6  GeV with the BESIII detector, we measure the absolute branching fraction of the inclusive semileptonic Λ_{c}^{+} decay with a double-tag method. We obtain B(Λ_{c}^{+}→Xe^{+}ν_{e})=(3.95±0.34±0.09)%, where the first uncertainty is statistical and the second systematic. Using the known Λ_{c}^{+} lifetime and the charge-averaged semileptonic decay width of nonstrange charmed mesons (D^{0} and D^{+}), we obtain the ratio of the inclusive semileptonic decay widths Γ(Λ_{c}^{+}→Xe^{+}ν_{e})/Γ[over ¯](D→Xe^{+}ν_{e})=1.26±0.12.

Measurement of the Branching Fraction For the Semileptonic Decay D^{0(+)}→π^{-(0)}μ^{+}ν_{μ} and Test of Lepton Flavor Universality

Using a data sample corresponding to an integrated luminosity of 2.93  fb^{-1} taken at a center-of-mass energy of 3.773 GeV with the BESIII detector operated at the BEPCII collider, we perform an analysis of the semileptonic decays D^{0(+)}→π^{-(0)}μ^{+}ν_{μ}. The branching fractions of D^{0}→π^{-}μ^{+}ν_{μ} and D^{+}→π^{0}μ^{+}ν_{μ} are measured to be (0.272±0.008_{stat}±0.006_{syst})% and (0.350±0.011_{stat}±0.010_{syst})%, respectively, where the former is of much improved precision compared to previous results and the latter is determined for the first time. Using these results along with previous BESIII measurements of D^{0(+)}→π^{-(0)}e^{+}ν_{e}, we calculate the branching fraction ratios to be R^{0}≡B_{D^{0}→π^{-}μ^{+}ν_{μ}}/B_{D^{0}→π^{-}e^{+}ν_{e}}=0.922±0.030_{stat}±0.022_{syst} and R^{+}≡B_{D^{+}→π^{0}μ^{+}ν_{μ}}/B_{D^{+}→π^{0}e^{+}ν_{e}}=0.964±0.037_{stat}±0.026_{syst}, which are compatible with the theoretical expectation of lepton flavor universality within 1.7σ and 0.5σ, respectively. We also examine the branching fraction ratios in different four-momentum transfer square regions, and find no significant deviations from the standard model predictions.

Observation of the Semileptonic Decay D^{0}→a_{0}(980)^{-}e^{+}ν_{e} and Evidence for D^{+}→a_{0}(980)^{0}e^{+}ν_{e}

Using an e^{+}e^{-} collision data sample of 2.93  fb^{-1} collected at a center-of-mass energy of 3.773 GeV by the BESIII detector at BEPCII, we report the observation of D^{0}→a_{0}(980)^{-}e^{+}ν_{e} and evidence for D^{+}→a_{0}(980)^{0}e^{+}ν_{e} with significances of 6.4σ and 2.9σ, respectively. The absolute branching fractions are determined to be B(D^{0}→a_{0}(980)^{-}e^{+}ν_{e})×B(a_{0}(980)^{-}→ηπ^{-})=[1.33_{-0.29}^{+0.33}(stat)±0.09(syst)]×10^{-4} and B(D^{+}→a_{0}(980)^{0}e^{+}ν_{e})×B(a_{0}(980)^{0}→ηπ^{0})=[1.66_{-0.66}^{+0.81}(stat)±0.11(syst)]×10^{-4}. This is the first time the a_{0}(980) meson has been measured in a D^{0} semileptonic decay, which would open one more interesting page in the investigation of the nature of the puzzling a_{0}(980) states.

Measurement of the Absolute Branching Fraction of the Inclusive Decay Λ_{c}^{+}→Λ+X

Based on an e^{+}e^{-} collision data sample corresponding to an integrated luminosity of 567  pb^{-1} taken at the center-of-mass energy of sqrt[s]=4.6  GeV with the BESIII detector, we measure the absolute branching fraction of the inclusive decay Λ_{c}^{+}→Λ+X to be B(Λ_{c}^{+}→Λ+X)=(38.2_{-2.2}^{+2.8}±0.9)% using the double-tag method, where X refers to any possible final state particles. In addition, we search for direct CP violation in the charge asymmetry of this inclusive decay for the first time, and obtain A_{CP}≡[B(Λ_{c}^{+}→Λ+X)-B(Λ[over ¯]_{c}^{-}→Λ[over ¯]+X)]/[B(Λ_{c}^{+}→Λ+X)+B(Λ[over ¯]_{c}^{-}→Λ[over ¯]+X)]=(2.1_{-6.6}^{+7.0}±1.6)%, a statistically limited result with no evidence of CP violation.

Observation of a_{0}^{0}(980)-f_{0}(980) Mixing

We report the first observation of a_{0}^{0}(980)-f_{0}(980) mixing in the decays of J/ψ→ϕf_{0}(980)→ϕa_{0}^{0}(980)→ϕηπ^{0} and χ_{c1}→a_{0}^{0}(980)π^{0}→f_{0}(980)π^{0}→π^{+}π^{-}π^{0}, using data samples of 1.31×10^{9}  J/ψ events and 4.48×10^{8}  ψ(3686) events accumulated with the BESIII detector. The signals of f_{0}(980)→a_{0}^{0}(980) and a_{0}^{0}(980)→f_{0}(980) mixing are observed at levels of statistical significance of 7.4σ and 5.5σ, respectively. The corresponding branching fractions and mixing intensities are measured and the constraint regions on the coupling constants, g_{a_{0}K^{+}K^{-}} and g_{f_{0}K^{+}K^{-}}, are estimated. The results improve the understanding of the nature of a_{0}^{0}(980) and f_{0}(980).

Precision Measurement of the e^{+}e^{-}→Λ_{c}^{+}Λ[over ¯]_{c}^{-} Cross Section Near Threshold

The cross section of the e^{+}e^{-}→Λ_{c}^{+}Λ[over ¯]_{c}^{-} process is measured with unprecedented precision using data collected with the BESIII detector at sqrt[s]=4574.5, 4580.0, 4590.0 and 4599.5 MeV. The nonzero cross section near the Λ_{c}^{+}Λ[over ¯]_{c}^{-} production threshold is cleared. At center-of-mass energies sqrt[s]=4574.5 and 4599.5 MeV, the higher statistics data enable us to measure the Λ_{c} polar angle distributions. From these, the Λ_{c} electric over magnetic form-factor ratios (|G_{E}/G_{M}|) are measured for the first time. They are found to be 1.14±0.14±0.07 and 1.23±0.05±0.03, respectively, where the first uncertainties are statistical and the second are systematic.