Antibody-drug conjugates transform the outcome of individuals with low-HER2-expression advanced breast cancer.

Antibody-drug conjugates (ADCs)-a groundbreaking class of agents for targeted oncological therapies-consist of monoclonal antibodies with strong antigenic specificity coupled with highly active cytotoxic agents (also referred to as "payloads"). Over the past 2 decades, breast cancer research has evolved into a focal point for the research and development of ADCs, leading to several recent landmark publications. These advancements are ushering in a transformative era in breast cancer treatment and redefining conventional classifications by introducing a prospective subtype termed "HER2-low." The latest iterations of ADCs have demonstrated enhanced efficacy in disease management through the optimization of various factors, notably the incorporation of the bystander effect. These conjugates are no longer limited to the oncogenic driver human epidermal growth factor receptor 2 (HER2). Other antigens, including human epidermal growth factor receptor 3 (HER3), trophoblast cell surface antigen 2 (Trop-2), zinc transporter ZIP6 (LIV-1), and folate receptor α (FRα), have recently emerged as intriguing tumor cell surface nondriver gene targets for ADCs, each with one or more specific ADCs that showed encouraging results in the breast cancer field. This article reviews recent advances in the application of ADCs in the treatment of HER2-low breast cancer. Additionally, this review explores the underlying factors contributing to the impact of target selection on ADC efficacy to provide new insights for optimizing the clinical application of ADCs in individuals with low HER2 expression in advanced breast cancer.

HIV-1 molecular transmission network and drug resistance in Chongqing, China, among men who have sex with men (2018-2021).

BACKGROUND: Over the past few years, HIV transmission among men who have sex with men (MSM) in China has increased significantly. Chongqing, located in the southwest of China, has the highest prevalence of HIV among MSM in the country. METHODS: Blood samples were taken from 894 MSM in Chongqing who had recently been diagnosed with HIV-1 infection and had not yet started getting treatment. In order to determine the distribution of HIV-1 subtypes, transmitted drug resistance, and assessments of molecularly transmitted clusters, we sequenced the Pol genes and employed them in phylogenetic analysis. The genetic distance between molecular clusters was 1.5%. To find potential contributing factors, logistic regression analyses were performed. RESULTS: Of the 894 HIV-1 pol sequences acquired from study participants, we discovered that CRF07_BC (73.6%) and CRF01_AE (19.6%) were the two most prevalent HIV-1 genotypes in Chongqing among MSM, accounting for 93.2% of all infections. In addition, CRF08_BC (1.1%), B subtype (1.0%), CRF55_01B (3.4%), and URF/Other subtypes (1.3%) were less frequently observed. Among MSM in Chongqing, transmitted drug resistance (TDR) was reported to be present at a rate of 5.6%. 48 clusters with 600 (67.1%, 600/894) sequences were found by analysis of the molecular transmission network. The distributions of people by age, sexual orientation, syphilis, and genotype were significantly differentially related to being in clusters, according to the multivariable logistic regression model. CONCLUSION: Despite the low overall prevalence of TDR, the significance of genotypic drug resistance monitoring needs to be emphasized. CRF07_BC and CRF01_AE were the two main genotypes that created intricate molecular transmission networks. In order to prevent the expansion of molecular networks and stop the virus's spread among MSM in Chongqing, more effective HIV intervention plans should be introduced.

Pickering emulsion stabilized by casein-caffeic acid covalent nanoparticles to enhance the bioavailability of curcumin in vitro and in vivo.

BACKGROUND: In recent years, the design of food-grade Pickering emulsion delivery systems has become an effective strategy for improving the low bioavailability of bioactive substances. Protein-based Pickering emulsions have received extensive attention because of a high biocompatibility and loading capacity. The bioavailability of active substances is mainly evaluated by simulating in vitro gastrointestinal digestion. As a model organism for antioxidation and anti-aging, Caenorhabditis elegans can provide additional biological information for the in vivo utilization of active substances. RESULTS: After the introduction of caffeic acid, the average particle size and Zeta potential of the casein-caffeic acid covalent complex nanoparticles (CCP) were 171.11 nm and - 37.73 mV, respectively. The three-phase contact angle was also increased to 89.8°. By using CCP to stabilize Pickering emulsion (CCE), the retention quantity of the embedded curcumin increased by 2.19-fold after 28 days. In the simulated gastric digestion, curcumin degradation in CCE was reduced by 61.84%, released slowly in the intestinal environment, and the final bioaccessibility was increased by 1.90-fold. In C. elegans, CCE significantly reduced ROS accumulation, increased SOD activity by 2.01-fold and CAT activity by 2.30-fold, decreased MDA content by 36.76%, prolonging the lifespan of nematodes by 13.33% under H2 O2 stimulation and improving bioavailability in vivo. CONCLUSION: The results indictae that CCP-stabilized Pickering emulsion can efficiently implement the physiological activities of bioactive compounds in vitro digestion and C. elegans, and thus it can be regarded as a reliable delivery system for food and medicine. © 2023 Society of Chemical Industry.

Capsaicin inhibits the stemness of anaplastic thyroid carcinoma cells by triggering autophagy-lysosome mediated OCT4A degradation.

Capsaicin (CAP) is a well-known anti-cancer agent. Recently, we reported capsaicin-induced apoptosis in anaplastic thyroid cancer (ATC) cells. It is well accepted that the generation of cancer stem cells (CSCs) is responsible for the dedifferentiation of ATC, the most lethal subtype of thyroid cancer with highly dedifferentiation status. Whether CAP inhibited the ATC growth through targeting CSCs needed further investigation. In the present study, CAP was found to induce autophagy in ATC cells through TRPV1 activation and subsequent calcium influx. Meanwhile, CAP dose-dependently decreased the sphere formation capacity of ATC cells. The stemness-inhibitory effect of CAP was further by extreme limiting dilution analysis (ELDA). CAP significantly decreased the protein level of OCT4A in both 8505C and FRO cells. Furthermore, CAP-induced OCT4A degradation was reversed by autophagy inhibitors 3-MA and chloroquine, BAPTA-AM and capsazepine, but not proteasome inhibitor MG132. Collectively, our study firstly showed CAP suppressed the stemness of ATC cells partially via calcium-dependent autophagic degradation of OCT4A. Our study lent credence to the feasible application of capsaicin in limiting ATC stemness.

Protective effect of surface-layer proteins from four Lactobacillus strains on tumor necrosis factor-α-induced intestinal barrier dysfunction.

BACKGROUND: The intestinal epithelium is considered the first defense protection against exogenous harmful substances, playing an indispensable role in regulating intestinal health. The protection offered by surface-layer proteins (Slps) from different Lactobacillus strains on an impaired intestinal barrier was investigated in this study. RESULTS: Four Slps pre-incubated for 6 h significantly prevented the reduced transepithelial electrical resistance value and increased paracellular permeability in tumor necrosis factor (TNF)-α-induced Caco-2 monolayers. TNF-α induced lower protein expression of occludin and zonula occludens-1, and abnormal distributions of occludin and zonula occludens-1 were ameliorated by four Slps as well. Additionally, four Slps weakened TNF-α-evoked interleukin-8 secretion and nuclear factor-κB activation. CONCLUSION: Four Slps from different strains prevent the intestinal barrier from TNF-α-induced dysfunction through blocking the nuclear factor-κB signaling pathway. © 2022 Society of Chemical Industry.

Vitamin C induces ferroptosis in anaplastic thyroid cancer cells by ferritinophagy activation.

Anaplastic thyroid cancer (ATC) is a rare but highly lethal disease. So far, there is no available established treatment which can prolong its survival. In this regard, effective therapies are urgently needed. Vitamin C widely serves as an anti-cancer agent. However, the potential effects of vitamin C against thyroid tumorigenesis remained unclear. The present study demonstrated that vitamin C could significantly inhibit ATC cells growth through ferroptosis activation, evidenced by the GPX4 inactivation, ROS accumulation and iron-dependent lipid peroxidation. Our results demonstrated that vitamin C treatment induced ferritinophagy and subsequent degradation of ferritin, leading to the release of free iron. Excessive iron further triggered ROS generation via Fenton reaction. The positive feedback mediated by ROS and iron sustained lipid peroxidation and further resulted in ferroptosis of ATC cells. The better understanding of the anti-cancer mechanisms of vitamin C provides a potential strategy for ATC therapy.

Realistic performance analysis for visible light communication with random receivers.

In previous studies, the receivers in indoor visible light communication (VLC) were usually fixed. However, in reality, the receivers in VLC have random locations and orientations. Therefore, it is important to consider these random factors for performance analysis in VLC. In this paper, we consider a typical VLC system with a fixed transmitter and a random receiver. Two types of receivers are investigated: (1) those with random location and (2) those with random orientation. Based on the established system model, the statistical characteristics of the channel were obtained, and closed-form expressions of the average channel capacity and the outage probability were derived, respectively. Finally, numerical results verified the accuracy of derived theoretical expressions. Moreover, the effects of the nominal optical intensity, the dimming target, the transmitter height, the receiver zone's radius, the outage threshold, and the Lambertian emission order on system performance were also provided.

Energy-Efficient Trajectory Optimization for UAV-Based Hybrid FSO/RF Communications with Buffer Constraints.

This paper focuses on an unmanned aerial vehicle (UAV) assisted hybrid free-space optical (FSO)/radio frequency (RF) communication system. Considering the rate imbalance between the FSO and RF links, a buffer is employed at the UAV. Initially, theoretical models of energy consumption and throughput are obtained for the hybrid system. Based on these models, the theoretical expression of the energy efficiency is derived. Then, a nonconvex trajectory optimization problem is formulated by maximizing the energy efficiency of the hybrid system under the buffer constraint, velocity constraint, acceleration constraint, start-end position constraint, and start-end velocity constraint. By using the sequential convex optimization and first-order Taylor approximation, the nonconvex problem is transformed into a convex one. An iterative algorithm is proposed to solve the problem. Numerical results verify the efficiency of the proposed algorithm and also show the effects of buffer size on a UAV's trajectory.

Trends of Human Immunodeficiency Virus, Syphilis, and Hepatitis C Infections Among Men Who Have Sex With Men in Chongqing, China: A Serial Cross-sectional Survey From 2011 to 2018.

BACKGROUND: Human immunodeficiency virus (HIV) prevalence and incidence rates have expeditiously increased among Chongqing men who have sex with men (MSM) over the past decade. This study investigated the trends of HIV, syphilis, and hepatitis C virus (HCV) infections and behavioral attributes of Chongqing MSM. METHODS: Chongqing MSM who were 18 years or older were recruited annually from 2011 to 2018. Interviewer-administered paper-pencil interviews were used to collect demographics, behavioral information, and sexually transmitted diseases history. Blood samples were collected for the tests of HIV, syphilis, and HCV. A stepwise regression model was conducted to assess the associations of demographics, behaviors, and syphilis and HCV infections with HIV infection. RESULTS: A total of 4900 MSM participated in the study. The average HIV, syphilis, and HCV prevalence over 8 years were 15.4%, 4.0%, and 0.3%, respectively. The HIV prevalence ranged from 13.5% to 16.4%. Syphilis and HCV were generally low and stable across years. An increased proportion of participants received HIV counseling, testing, and condoms. Multivariable regression indicated that HIV-positive MSM were more likely to be older, married, and less educated, and they were more likely to perform unprotected anal intercourse with male partners in the past 6 months, have syphilis, and less likely to receive HIV counseling, testing, condoms, and peer education in the past year. CONCLUSIONS: The HIV counseling, testing, and peer education programs showed a negative association with HIV-positive status among Chongqing MSM. The HIV prevalence is still high. More programs must be implemented to effectively curb the HIV epidemic.

Trends of HIV, hepatitis C virus and syphilis seroprevalence among injection and non-injection drug users in southwestern China, 2010-2017.

BACKGROUND: The primary risk of HIV transmission in China has shifted from injecting drug use (IDU) to sexual contact since 2006. We evaluated the prevalence trends of HIV, hepatitis C virus (HCV), syphilis, and sexual and drug use behaviors among drug users. Methods: People who use drugs participated in any of four rounds of cross-sectional surveys during 2010-2017 in Chongqing. Participants were tested for HIV, HCV, and syphilis. Questionnaire interviewing was conducted to collect behavioral information. Chi-square and trend tests were employed to assess the changes in diseases and behaviors over time. Results: A total of 8,171 people who inject drugs (PWID) and 5,495 non-injection drug users (NIDU) were included in the analyses. HIV prevalence among PWID in four rounds of the survey in 2010-11, 2012-13, 2014-15, and 2016-17 was 11.5%, 9.7%, 6.5%, and 6.9%, and among NIDU, 2.4%, 1.4%, 2.1% and 2.6%, respectively. HCV prevalence among PWID was 83.5%, 85.2%, 67.1% and 79.7% (P < 0.001), and among NIDU, 22.2%, 10.8%, 13.4% and 14.8%, (P < 0.001). Conclusions: The declining HIV and HCV prevalence among PWID is coincident with declining risky drug use behaviors. Tailored disease prevention and interventions targeting PWID and NIDU are needed.

Effect of Different Clarification Treatments on the Volatile Composition and Aromatic Attributes of 'Italian Riesling' Icewine.

The aim of this study was to evaluate the influence of clarification treatments on volatile composition and aromatic attributes of wine samples. 'Italian Riesling' icewines from the Hexi Corridor Region of China were clarified by fining agents (bentonite (BT) and soybean protein (SP)), membrane filtration (MF), and centrifugation (CF) methods. The clarity, physicochemical indexes, volatile components, and aromatic attributes of treated wines were investigated. Both the fining agents and mechanical clarification treatments increased the transmittance and decreased the color intensity of icewine samples. Bentonite fining significantly influenced the total sugar content, total acidity and volatile acidity. Total acidity decreased 2-3.5% and volatile acidity 2-12%. MF showed the greatest influence on total phenol content, decreasing the initial content by 12%, while other treatments by less than 8%. Volatile analysis indicated that both the categories and contents of volatile compounds of wine samples decreased. MF treatment showed the most significant influence, while SP fining showed much lower impact. Odor activity values indicated the compound with the highest odor activity in Italian Riesling icewines was ß-damascenone. For this compound, BT and SP did not show significant differences, however, in MF and CF it decreased by 20% and 63%, respectively. Furthermore, with high impact on aroma were: ethyl hexanoate which reduced by 20-80% especially in MF; rose oxide which extremely reduced in MF and undetected in BT, SP, and CF; isoamyl acetate which reduced by 3-33% and linalool decreased by 10-20% and undetected for BT. Principle component analysis indicated that icewine clarified by different methods could be distinguished and positively correlated with odor-active compounds. Floral and fruity were the dominant aroma series in icewine samples followed by fatty, earthy, spicy, vegetative and pungent flavor. The total odor active value of these series significantly (p < 0.5) decreased in different clarification treatments. Sensory evaluation showed similar results, but the SP and CF wine samples achieved better sensory quality. This study provides information that could help to optimize the clarification of ice wines.

What has changed HIV and syphilis infection among men who have sex with men (MSM) in Southwest China: a comparison of prevalence and behavioural characteristics (2013-2017).

BACKGROUND: Chongqing reportedly has a large MSM population and a high STI prevalence in previous studies. However, most studies are attributed to independent cross-sectional studies, few studies have investigated trends in the prevalence of syphilis and HIV, as well as behavioural characteristics among MSM using serial surveillance surveys. METHODS: Data were collected in Chongqing through face-to-face questionnaire interview and laboratory testing in Chongqing. The respondents were recruited among MSM by snowball sampling from May 2013 to December 2017. The self-report questionnaire primarily included socio-demographics, HIV knowledge, and HIV-related behaviour characteristics over the year. Blood specimens were tested to diagnose HIV and syphilis infection by Chongqing CDC. Cochran-Armitage trend test and multivariate logistic regression were conducted to compare the changes in STI prevalence and independent behavioural factors among MSM. RESULTS: There were 6568 eligible participants (98.4%). The overall HIV prevalence was 20.5% among MSM in Chongqing, with a decrease from 23.0% in 2013 to 19.2% in 2017. The overall syphilis prevalence was 5.8%, with an increase from 3.2% in 2013 to 6.7% in 2017. The proportion of consistent condom use (CCU) during anal intercourse (46.3 to 57.7%, P<0.001),CCU with regular male partners(47.7 to 59.7%, P<0.001), CCU with casual male partners (51.5 to 62.3%, P<0.001) and drug use during anal intercourse (0.3 to 1.4%, P<0.05) were increasing. By contrast, a significant decrease was reported in the percentage of MSM with more than two regular male partners (66.0 to 21.4%, P<0.001) and more than two casual male partners (38.3 to 20.7%, P<0.001). A significant difference was observed in syphilis infection, testing for HIV antibodies and drug use during anal intercourse in the past years between the HIV-positive and HIV-negative respondents. CONCLUSION: A decreasing trend of HIV prevalence was showed during among MSM from 2013 to 2017 in Chongqing. While gradual reduction of high-risk behaviors along with HIV prevalence supported development of STI counselling and testing, increasing syphilis infection and drug use during anal intercourse warrants further understanding.

Real-Time Large-Scale Dense Mapping with Surfels.

Real-time dense mapping systems have been developed since the birth of consumer RGB-D cameras. Currently, there are two commonly used models in dense mapping systems: truncated signed distance function (TSDF) and surfel. The state-of-the-art dense mapping systems usually work fine with small-sized regions. The generated dense surface may be unsatisfactory around the loop closures when the system tracking drift grows large. In addition, the efficiency of the system with surfel model slows down when the number of the model points in the map becomes large. In this paper, we propose to use two maps in the dense mapping system. The RGB-D images are integrated into a local surfel map. The old surfels that reconstructed in former times and far away from the camera frustum are moved from the local map to the global map. The updated surfels in the local map when every frame arrives are kept bounded. Therefore, in our system, the scene that can be reconstructed is very large, and the frame rate of our system remains high. We detect loop closures and optimize the pose graph to distribute system tracking drift. The positions and normals of the surfels in the map are also corrected using an embedded deformation graph so that they are consistent with the updated poses. In order to deal with large surface deformations, we propose a new method for constructing constraints with system trajectories and loop closure keyframes. The proposed new method stabilizes large-scale surface deformation. Experimental results show that our novel system behaves better than the prior state-of-the-art dense mapping systems.

Mechanisms of Nα-lauroyl arginate ethyl ester against Penicillium digitatum and Pectobacterium carotovorum subsp. carotovorum.

The purpose of this study was to investigate the antimicrobial activity and mechanisms of Nα-lauroyl arginate ethyl ester (LAE) against Penicillium digitatum and Pectobacterium carotovorum subsp. carotovorum. The minim inhibitory concentrations of LAE against P. digitatum and P. carotovorum were found to be 400 and 25 µg/ml, respectively. Loss of intracellular protein and nucleic acid increased significantly, and membrane permeability reached 76.28, 54.29 and 85.20%, respectively, when 400 µg/ml of LAE was applied to the hyphae and spores of P. digitatum and to P. carotovorum. Flow cytometry showed that LAE reduced the membrane potential, and the depolarization ratios of P. digitatum and P. carotovorum were 98.19 and 97.25% (P < 0.05), respectively. Transmission electron microscopy photos revealed that LAE caused a rough surface, irregular cellular organelles, protoplast shrinkage, intracytoplasmic coagulation and empty cavities in all three cell types. These results showed that LAE had notable ability to damage the structure of fungal and bacterial cells, making it a possible alternative chemical for use in the preservation of fruits and vegetables.

Curcumin inhibits metastasis in human papillary thyroid carcinoma BCPAP cells via down-regulation of the TGF-ß/Smad2/3 signaling pathway.

Thyroid cancers usually possess a good prognosis while the risks of recurrence and metastasis turn out to be a disturbing issue. Curcumin [bis(4-hydroxy-3-methoxy-phenyl)-1,6-heptadiene-3,5-dione] is a natural polyphenolic compound mainly found in turmeric (Curcuma longa). Our previous studies have demonstrated that curcumin showed proliferation-inhibitory and apoptosis-inducing effects on K1 papillary thyroid cancer cells. However, the mechanism underlying the inhibition effects of curcumin on thyroid cancer cells remains unclear. Herein, we demonstrated that curcumin remarkably increased the expression of the epithelial marker E-cadherin and repressed the expression of the mesenchymal marker vimentin in human papillary thyroid carcinoma BCPAP cells. Curcumin also suppressed multiple metastatic steps of BCPAP cells, including cell attachment, spreading as well as migration. In addition, the transcription, secretion and activation of matrix metalloproteinases (MMPs) induced by transforming growth factor-ß1 (TGF-ß1) in BCPAP cells were mitigated upon curcumin treatment. Further evidence showed that curcumin decreased TGF-ß1-mediated phosphorylation of Smad2 and Smad3. These results revealed that curcumin inhibited the TGF-ß1-induced epithelial-mesenchymal transition (EMT) via down-regulation of Smad2/3 signaling pathways. Our findings provide new evidence that the anti-metastatic and anti-EMT activities of curcumin may contribute to the development of chemo-preventive agents for thyroid cancer treatment.

Investigating HIV Infection and HIV Incidence Among Chinese Men Who Have Sex with Men with Recent Sexual Debut, Chongqing, China, 2011.

HIV among men who have sex with men (MSM) with recent male-male sexual debut, such as within the past 5 years, may be a proxy for recent HIV infection. Using this definition, we explored factors associated with HIV infection in this group to understand the evolving HIV epidemic among MSM in Chongqing. We conducted a cross-sectional respondent-driven sampling survey among Chongqing MSM in 2011. Computer-assisted, self-administered questionnaires were used and blood specimens were collected for HIV and syphilis testing. Three hundred and ninety-one unique MSM were recruited of which 65.7 % (257) had their sexual debut with another man in the past 5 years. HIV prevalence among men with recent sexual debut was 18.7 % suggesting a possible HIV incidence of 3.7 %. Multivariable analysis among men with recent sexual debut suggests that lower education, having more than one male partner, and currently being infected with syphilis are associated with HIV among men with recent sexual debut. HIV prevalence is high among MSM with recent sexual debut in Chongqing, which may be a proxy a high incidence rate. HIV prevention efforts should focus on STD reduction among those MSM with lower educational attainment.

Hydrophobicity of whey protein hydrolysates enhances the protective effect against oxidative damage on PC 12 cells.

The relationship between hydrophobicity and the protective effect of whey protein hydrolysates (WPHs) against oxidative stress was studied. Whey protein was first hydrolysed by pepsin and trypsin to obtain WPHs. After absorbed by macroporous adsorption resin DA201-C, three fractions named as M20, M40, and M60 were eluted by various concentrations of ethanol. The hydrophobicity showed a trend of increase from M20 to M60. Antioxidant ability test in vitro indicated that all the three components of WPHs displayed reasonably good antioxidant ability. Moreover, with the increase of hydrophobicity, antioxidant ability of WPHs improved significantly. Then rat pheochromocytoma line 12 (PC12) cells oxidative model was built to evaluate the suppression of oxidative stress of three components on PC12 cells induced by H2O2. Morphological alterations, cell viability, apoptosis rate, and intracellular antioxidase system tests all indicated that WPHs exert significant protection on PC cells against H2O2-induced damage. Among them, M60 had the highest protective effect by increasing 19·3% cell survival and reducing 28·6% cell apoptosis. These results suggested hydrophobicity of WPHs was contributing to the antioxidant ability and the protective effect against oxidative damage.

Improvement of ACE inhibitory activity of casein hydrolysate by Maillard reaction with xylose.

BACKGROUND: The Maillard reaction is widely used to improve the functional properties or biological activities of food. The purpose of this study was to investigate the effect of the Maillard reaction on angiotensin I converting enzyme (ACE) inhibitory activity in a casein hydrolysate-xylose system. RESULTS: Two-step hydrolysis was used to prepare casein ACE inhibitory peptides. Maillard reaction products (MRPs) were prepared by heating hydrolyzed casein with xylose at pH 8.0, 110 °C for up to 16 h. The results showed that the content of free amino group decreased (P < 0.05); however, browning intensity and absorbance at 294 nm increased because of the Maillard reaction (P < 0.05). The ACE inhibitory activity improved greatly within 2 h (from 63.48% to 90.23%), which was mainly due to carbonyl ammonia condensation reaction in the MRPs. CONCLUSION: The study shows that the Maillard reaction under appropriate conditions can improve the ACE inhibitory activity of casein hydrolysate effectively.

Sexual partnerships with men and women among men who have sex with men in Beijing and Chongqing, China, 2010.

HIV is spreading among Chinese MSM and may possibly lead to infection of female partners. Pressure to marry may drive a greater proportion of Chinese MSM to have female partners than MSM elsewhere in the world. Measurement of the size of the potential risk to female partners of Chinese MSM is inconsistent in the literature. From samples of MSM in two Chinese cities, we documented numbers of sexual partners and sexual activity with those partners. About 500 MSM were sampled in each city. 11.0 and 12.6 % of men reported having any female partners in the past 6 months in Chongqing and Beijing, respectively. Men also reported that only 7.3 and 6.7 % of their entire partnerships were with women in Chongqing and Beijing, respectively. Defining transmission risk accounting for receptive anal sex among men and condom non-use with both male and female partners, 3.4 % of MSM in both Chongqing and Beijing would have the potential to transmit HIV to female partners. Only 9 (1.8 ) men in Chongqing and 2 (0.4 %) in Beijing were HIV-positive and also had unprotected intercourse with females. The majority of HIV transmission risk among MSM in China is not from MSM to females.

Multilevel ecological compensation policy design based on ecosystem service flow: A case study of carbon sequestration services in the Qinghai-Tibet Plateau.

Ecological compensation is an effective means to reconcile the imbalance of eco-social development between regions and promote enthusiasm for ecological environmental protection. There is some conformity between the theory of ecosystem service flow and ecological compensation, which provides new technical support for the formulation of ecological compensation policy. This study took the Qinghai-Tibet Plateau as the research area, adopted the breaking point model to obtain the spatial characteristics of carbon sequestration flow, and formulated a multilevel ecological compensation policy with Tibet as the design object. The results showed that most of the Qinghai-Tibet Plateau has a carbon sequestration surplus; the central and eastern Qinghai-Tibet Plateau, western Sichuan are successively carbon sequestration supply areas; the Chengdu Plain and Xinjiang were listed as carbon sequestration benefit areas; and the carbon sequestration tended to flow more closely between supply and benefit areas in proximity to each other. Nyingchi, Chamdo, Naqu and Shannan in Tibet need to receive a total ecological compensation of 393.21 million USD, of which 93.71 % is from the national level, 6.02 % is from carbon sequestration benefit areas in other provinces; furthermore, Lhasa and Shigatse in Tibet need to provide the remaining ecological compensation. This study offers innovations for the formulation of ecological compensation policies and provide a new theory for ecological environment management.