97 research outputs found

    HHMF: hidden hierarchical matrix factorization for recommender systems

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    Abstract(#br)Matrix factorization (MF) is one of the most powerful techniques used in recommender systems. MF models the (user, item) interactions behind historical explicit or implicit ratings. Standard MF does not capture the hierarchical structural correlations, such as publisher and advertiser in advertisement recommender systems, or the taxonomy (e.g., tracks, albums, artists, genres) in music recommender systems. There are a few hierarchical MF approaches, but they require the hierarchical structures to be known beforehand. In this paper, we propose a Hidden Hierarchical Matrix Factorization (HHMF) technique, which learns the hidden hierarchical structure from the user-item rating records. HHMF does not require the prior knowledge of hierarchical structure; hence, as opposed to..

    N-Glycosylation-Defective Splice Variants of Neuropilin-1 Promote Metastasis by Activating Endosomal Signals

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    Neuropilin-1 (NRP1) is an essential transmembrane receptor with a variety of cellular functions. Here, we identify two human NRP1 splice variants resulting from the skipping of exon 4 and 5, respectively, in colorectal cancer (CRC). Both NRP1 variants exhibit increased endocytosis/recycling activity and decreased levels of degradation, leading to accumulation on endosomes. This increased endocytic trafficking of the two NRP1 variants, upon HGF stimulation, is due to loss of N-glycosylation at the Asn150 or Asn261 site, respectively. Moreover, these NRP1 variants enhance interactions with the Met and β1-integrin receptors, resulting in Met/β1-integrin co-internalization and co-accumulation on endosomes. This provides persistent signals to activate the FAK/p130Cas pathway, thereby promoting CRC cell migration, invasion and metastasis. Blocking endocytosis or endosomal Met/β1-integrin/FAK signaling profoundly inhibits the oncogenic effects of both NRP1 variants. These findings reveal an important role for these NRP1 splice variants in the regulation of endocytic trafficking for cancer cell dissemination

    Driving force of condomless sex after online intervention among Chinese men who have sex with men

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    BACKGROUND: Condom use remains consistently low among Chinese men who have sex with men (MSM). This study aims to identify factors associated with condom use after online video intervention. METHODS: This is a secondary data analysis of data collected from an online non-inferiority trial comparing the effectiveness of two condom use promotion video interventions among Chinese MSM. Participants from the two groups were combined since the effectiveness of two video interventions were shown to be non-inferior. Univariable and multivariable logistic regression were used to identify factors associated with condomless sex after the intervention during the follow-up interval. RESULTS: Overall, 1173 participants were recruited at baseline and 791 (67.4%) completed the three-month follow-up survey. 57.3% (453/791) of the participants reported condomless sex after intervention in the three-month follow-up interval. MSM who have had sex under the influence of alcohol in the last 3 months (Odds Ratio(OR) = 1.90; 95% CI: 1.22, 2.97; Adjusted OR(AOR) = 1.79; 95% CI: 1.13, 2.83) and ever have had sex tourism (OR = 2.75; 95% CI: 1.34, 5.63; AOR = 2.40; 95% CI: 1.15, 5.07) at baseline were more likely to have condomless sex after intervention in the three-month follow-up period. MSM who had a higher level of community engagement in sexual health (OR = 0.54; 95% CI: 0.35, 0.82; AOR = 0.49; 95% CI: 0.32, 0.75 with substantial engagement) and who viewed additional condom promotion videos during the follow-up period by themselves (OR = 0.67; 95% CI = 0.50, 0.89; AOR = 0.67; 95% CI: 0.50, 0.91). were less likely to have condomless sex during the follow-up period. CONCLUSION: The intervention appeared to be effective among MSM who reported viewing additional condom promotion videos by themselves and more community engagement after the intervention. In MSM who reported risky sexual behaviors at baseline, the intervention appeared less effective. Tailored intervention videos that target particular subgroups, active in-person community engagement, and optimized intervention frequency should be considered in future sexual health interventions

    Pressured HIV testing "in the name of love": a mixed methods analysis of pressured HIV testing among men who have sex with men in China.

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    INTRODUCTION: HIV testing has rapidly expanded into diverse, decentralized settings. While increasing accessibility to HIV testing is beneficial, it may lead to unintended consequences such as being pressured to test. We examined the frequency, correlates and contexts of pressured HIV testing among Chinese men who have sex with men (MSM) using mixed methods. METHODS: We conducted an online survey of MSM (N = 1044) in May 2017. Pressured HIV testing was defined as being forced to test for HIV. We conducted logistic regression analysis to determine the associations between pressured HIV testing and socio-demographic and sexual behavioural factors. Follow-up interviews (n = 17) were conducted with men who reported pressured testing and we analysed qualitative data using a thematic analysis approach. RESULTS: Ninety-six men (9.2%) reported experiencing pressure to test for HIV. Regular male sex partners were the most common source of pressure (61%, 59/96), and the most common form of pressure was a threat to end a relationship with the one who was being pressured (39%, 37/96). We found a higher risk of pressured testing in men who had only used HIV self-testing compared to men who had never self-tested (AOR 2.39 (95%CI: 1.38 to 4.14)). However, this relationship was only significant among men with low education (AOR 5.88 (95% CI: 1.92 to 17.99)) and not among men with high education (AOR 1.62 (95% CI: 0.85 to 3.10)). After pressured testing, about half of men subsequently tested for HIV (55%, 53/96) without pressure - none reported being diagnosed with HIV. Consistent with this finding, qualitative data suggest that perceptions of pressure existed on a continuum and depended on the relationship status of the one who pressured them. Although being pressured to test was accompanied by negative feelings, men who were pressured into testing often changed their attitude towards HIV testing, testing behaviours, sexual behaviours and relationship with the one who pressured them to test. CONCLUSION: Pressured HIV testing was reported among Chinese MSM, especially from men with low education levels and men who received HIV self-testing. However, in some circumstances, pressure to test helped MSM in several ways, challenging our understanding of the role of agency in the setting of HIV testing

    Leading by Example: Web-Based Sexual Health Influencers Among Men Who Have Sex With Men Have Higher HIV and Syphilis Testing Rates in China

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    BACKGROUND: The spread of healthy behaviors through social networks may be accelerated by influential individuals. Previous studies have used lay health influencers to prevent sexually transmitted infections (STIs) among internet-using men who have sex with men (MSM). However, there is a lack of understanding of the characteristics of this key subset of MSM. OBJECTIVE: This study aimed to examine sociodemographic characteristics, HIV and syphilis testing, and sexual behaviors of Web-based MSM sexual health influencers (SHIs) in China, defined as individuals with relatively stronger influence on spreading HIV and STI information online. METHODS: A Web-based survey of MSM was conducted in August 2017 as a final follow-up of a randomized controlled trial promoting HIV testing in 8 Chinese cities. Men were recruited through a gay social networking mobile phone app and were included if they were born biologically male, aged 16 years and above, ever had sex with another man, and HIV negative or with unknown HIV status. Information regarding sociodemographic characteristics, sexual behaviors, and HIV and syphilis testing was obtained. We assessed men's Web-based sexual health influence using a standardized 6-item opinion leadership scale focused on HIV and STI information. Influencers were defined as those whose mean score ranked within the top 13% (a higher score means greater influence). We used multivariable linear and logistic regression models to measure Web-based sexual health influence's association with HIV and syphilis testing, controlling for intervention trial effects, age, education, income, and marital status. RESULTS: Overall, 1031 men completed the survey. Most men were younger than 30 years (819/1031, 79.43%) and had at least college education (667/1031, 64.69%). Influencers were more likely to get tested for HIV (73/132, 55.3% vs 337/899, 37.5%; P<.001) and syphilis (35/132, 26.5% vs 137/899, 15.2%; P=.001) in the last 3 months compared with noninfluencers. There were no significant differences in condomless sex with male partners (26/132, 19.7% vs 203/899, 22.6%; P=.46), mean number of male sex partners (1.32 vs 1.11; P=.16) in the last 3 months, and mainly meeting male sex partners online in the last 12 months (97/132, 73.5% vs 669/899, 74.4%; P=.82) between influencers and noninfluencers. Regression analyses showed that influencers had higher odds of HIV testing (adjusted odds ratio, AOR 2.16, 95% CI 1.48-3.17) and syphilis testing (AOR 1.99, 95% CI 1.28-3.10) in the last 3 months. CONCLUSIONS: We identified Web-based SHIs who might be more likely to help promote healthy HIV and syphilis testing behaviors through MSM populations. Leveraging existing influencers may help improve HIV and syphilis testing among their networks

    Role of Fractalkine/CX3CR1 Interaction in Light-Induced Photoreceptor Degeneration through Regulating Retinal Microglial Activation and Migration

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    Background: Excessive exposure to light enhances the progression and severity of some human retinal degenerative diseases. While retinal microglia are likely to be important in neuron damage associated with these diseases, the relationship between photoreceptor damage and microglial activation remains poorly understood. Some recent studies have indicated that the chemokine fractalkine is involved in the pathogenesis of many neurodegenerative diseases. The present study was performed to investigate the cross-talk between injured photoreceptors and activated retinal microglia, focusing on the role of fractalkine and its receptor CX3CR1 in light-induced photoreceptor degeneration. Methodology/Principal Findings: Both in vivo and in vitro experiments were involved in the research. In vivo, Sprague– Dawley rats were exposed to blue light for 24 hours. In vitro, the co-culture of primary retinal microglia and a photoreceptor cell line (661W cell) was exposed to blue light for five hours. Some cultures were pretreated by the addition of anti-CX3CR1 neutralizing antibody or recombinant fractalkine. Expression of fractalkine/CX3CR1 and inflammatory cytokines was detected by immunofluorescence, real-time PCR, Western immunoblot analysis, and ELISA assay. TUNEL method was used to detect cell apoptosis. In addition, chemotaxis assay was performed to evaluate the impact of soluble fractalkine on microglial migration. Our results showed that the expression of fractalkine that was significantly upregulated after exposure to light, located mainly at the photoreceptors. The extent of photoreceptor degeneration and microglial migratio
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