Real-time Short Video Recommendation on Mobile Devices

Short video applications have attracted billions of users in recent years, fulfilling their various needs with diverse content. Users usually watch short videos on many topics on mobile devices in a short period of time, and give explicit or implicit feedback very quickly to the short videos they watch. The recommender system needs to perceive users' preferences in real-time in order to satisfy their changing interests. Traditionally, recommender systems deployed at server side return a ranked list of videos for each request from client. Thus it cannot adjust the recommendation results according to the user's real-time feedback before the next request. Due to client-server transmitting latency, it is also unable to make immediate use of users' real-time feedback. However, as users continue to watch videos and feedback, the changing context leads the ranking of the server-side recommendation system inaccurate. In this paper, we propose to deploy a short video recommendation framework on mobile devices to solve these problems. Specifically, we design and deploy a tiny on-device ranking model to enable real-time re-ranking of server-side recommendation results. We improve its prediction accuracy by exploiting users' real-time feedback of watched videos and client-specific real-time features. With more accurate predictions, we further consider interactions among candidate videos, and propose a context-aware re-ranking method based on adaptive beam search. The framework has been deployed on Kuaishou, a billion-user scale short video application, and improved effective view, like and follow by 1.28%, 8.22% and 13.6% respectively.Comment: Accepted by CIKM 2022, 10 page

Activated mouse CD4+Foxp3−CD4^+Foxp3^− T cells facilitate melanoma metastasis via Qa-1-dependent suppression of NK-cell cytotoxicity

The regulatory activities of mouse $CD^4+Foxp3^+$ T cells on various immune cells, including NK cells, have been well documented. Under some conditions, conventional $CD4^+Foxp3^−$ T cells in the periphery are able to acquire inhibitory function on other T cells, but their roles in controlling innate immune cells are poorly defined. As a potential cellular therapy for cancer, ex vivo activated $CD4^+Foxp3^−$ effector T cells are often infused back in vivo to suppress tumor growth and metastasis. Whether such activated T cells could affect NK-cell control of tumorigenesis is unclear. In the present study, we found that mitogen-activated $CD4^+Foxp3^−$ T cells exhibited potent suppressor function on NK-cell proliferation and cytotoxicity in vitro, and notably facilitated B16 melanoma metastasis in vivo. Suppression of NK cells by activated $CD4^+Foxp3^−$ T cells is cell-cell contact dependent and is mediated by Qa-1:NKG2A interaction, as administration of antibodies blocking either Qa-1 or NKG2A could completely reverse this suppression, and significantly inhibited otherwise facilitated melanoma metastasis. Moreover, activated $CD4^+Foxp3^−$ cells from Qa-1 knockout mice completely lost the suppressor activity on NK cells, and failed to facilitate melanoma metastasis when transferred in vivo. Taken together, our findings indicate that innate anti-tumor response is counter regulated by the activation of adaptive immunity, a phenomenon we term as “activation-induced inhibition”. Thus, the regulatory role of activated $CD4^+Foxp3^−$ T cells in NK-cell activity must be taken into consideration in the future design of cancer therapies

Cu/Fe-Cocatalyzed Meyer–Schuster-like Rearrangement of Propargylic Amines: Direct Access to <i>E</i>‑β-Aminoacryaldehydes

A simple and efficient method for the synthesis of β-aminoacryaldehydes via Cu­(OAc)₂·H₂O and FeCl₃ cocatalyzed Meyer–Schuster-Like rearrangement of propargylic amines was developed. The reactions proceed selectively as the <i>E</i>-isomers in generally good yields under aerobic conditions, and are compatible with a broad range of functional groups. This method combines C–N bond cleavage as well as the <i>N</i>-aryl group migration and provides a practical and mild synthetic approach to α,β-unsaturated carbonyl compounds, which are useful precursors in a variety of functional group transformations

Enhancement of Immune Response and Anti-Infection of Mice by Porcine Antimicrobial Peptides and Interleukin-4/6 Fusion Gene Encapsulated in Chitosan Nanoparticles

In order to develop a novel and effective immunoregulator to enhance both the immune response and antimicrobial function, a recombinant eukaryotic expression plasmid-pVAX1 co-expressing fusion cathelicidin antimicrobial peptides (CAMPs) and fusion porcine interleukin-4/6 gene (IL-4/6) was constructed and encapsulated in chitosan nanoparticles (CS-VAP4/6), prepared by the ionotropic gelation method. Four-week-old female Kunming mice were divided into three groups and intramuscularly injected, respectively, with CS-VAP, CS-VAP4/6, and CS-pVAX1. On 28 days post-inoculation, the mice were challenged by intraperitoneal injection with Staphylococcus aureus (ATCC 25923) and Escherichia coli (ATCC 25922); IgG, IgG1 and IgG2a, CD4+, and CD8+ T cells increased significantly in the VAP- and VAP4/6- treated mice, detected by ELISA and flow cytometry, correspondingly (p &lt; 0.05). As analyzed by qPCR, expression levels of Toll-like receptor (TLR) 1, TLR4, TLR6, TLR9, IL-1, IL-2, IL-4, IL-6, IL-7, IL-12, IL-15, IL-23, Tumor Necrosis Factor (TNF)-&alpha;, and Interferon-gamma (IFN-&gamma;) genes were also significantly up-regulated in comparison with those of the control mice (p &lt; 0.05). Their immunological markers were elevated significantly to different degrees in CS-VAP4/6-treated mice compared with CS-VAP in different days post-inoculation (p &lt; 0.05). After challenge with E. coli and Staphylococcus aureus, most of the VAP- and VAP4/6- treated mice survived, and no symptoms of bacterial infection were observed. In contrast, 80% of control mice died of infection. Among the treated groups, VAP4/6 had a stronger resistance against challenge with E. coli infection. These results demonstrated that the fusion gene of antimicrobial peptide and interleukin-4/6 has the promising potential as a safe and effective immunomodulator for the control of bacterial infections

Degradation of Host Proteins and Apoptosis Induced by Foot-and-Mouth Disease Virus 3C Protease

Foot-and-mouth disease (FMD), induced by the foot-and-mouth disease virus (FMDV), is a highly contagious disease of cloven-hoofed animals. Previous studies have reported that FMDV 3C protease could degrade multiple host proteins; however, the degradation mechanism mediated by FMDV 3C is still unclear. Here, we found that transient expression of FMDV 3C degraded various molecules in NF-&kappa;B signaling in a dose-dependent manner, and the proteolytic activity of FMDV 3C is important for inducing degradation. Additionally, 3C-overexpression was associated with the induction of apoptosis. In this study, we showed that an apoptosis inhibitor CrmA abolished the ability of 3C to degrade molecules in NF-&kappa;B signaling. Further experiments using specific caspase inhibitors confirmed the irrelevance of caspase3, caspase8, and caspase9 activity for degradation induced by 3C. Altogether, these results suggest that FMDV 3C induces the widespread degradation of host proteins through its proteolytic activity and that the apoptosis pathway might be an important strategy to mediate this process. Further exploration of the relationship between apoptosis and degradation induced by 3C could provide novel insights into the pathogenic mechanisms of FMDV

Copper-Catalyzed C(sp²)–H Amidation with Azides as Amino Sources

A copper-catalyzed C–H amidation process, with azides as amino sources under oxidant-free conditions, has been developed. When <i>N</i>-heterocycles were employed as directing groups, sulfonylazide and benzoylazide could be used as amidating reagents to provide corresponding <i>N</i>-arylamides. When amidines or imine were used, tandem C–N/N–N bond formation occurred to afford indazole derivatives in one pot

Preparation and Optimization of Triptolide-Loaded Solid Lipid Nanoparticles for Oral Delivery with Reduced Gastric Irritation

Triptolide (TP) often causes adverse reactions in the gastrointestinal tract when it is administered orally. This study aimed to prepare and optimize triptolide-loaded solid lipid nanoparticles (TP-SLN) with reduced gastric irritation. The microemulsion technique was used to formulate TP-SLN employing a five-level central composite design (CCD) that was developed for exploring the optimum levels of three independent variables on particle size, encapsulation efficiency (EE) and drug loading (DL). Quadratic polynomial models were generated to predict and evaluate the three independent variables with respect to the three responses. The optimized TP-SLN was predicted to comprise fraction of lipid of 49.73%, surfactant to co-surfactant ratio of 3.25, and lipid to drug ratio of 55.27, which showed particle size of 179.8 ± 5.7 nm, EE of 56.5 ± 0.18% and DL of 1.02 ± 0.003% that were in good agreement with predicted values. In addition, the optimized nanoparticles manifested a sustained-release pattern in vitro and were stable during 3 h of incubation in simulated gastric fluids without significant size change and the majority (91%) of the drug was protected. Furthermore, the nanoparticles did not show obvious gastric irritation caused by oral administration of TP in rats

Preparation and Optimization of Triptolide-Loaded Solid Lipid Nanoparticles for Oral Delivery with Reduced Gastric Irritation

Triptolide (TP) often causes adverse reactions in the gastrointestinal tract when it is administered orally. This study aimed to prepare and optimize triptolide-loaded solid lipid nanoparticles (TP-SLN) with reduced gastric irritation. The microemulsion technique was used to formulate TP-SLN employing a five-level central composite design (CCD) that was developed for exploring the optimum levels of three independent variables on particle size, encapsulation efficiency (EE) and drug loading (DL). Quadratic polynomial models were generated to predict and evaluate the three independent variables with respect to the three responses. The optimized TP-SLN was predicted to comprise fraction of lipid of 49.73%, surfactant to co-surfactant ratio of 3.25, and lipid to drug ratio of 55.27, which showed particle size of 179.8 ± 5.7 nm, EE of 56.5 ± 0.18% and DL of 1.02 ± 0.003% that were in good agreement with predicted values. In addition, the optimized nanoparticles manifested a sustained-release pattern in vitro and were stable during 3 h of incubation in simulated gastric fluids without significant size change and the majority (91%) of the drug was protected. Furthermore, the nanoparticles did not show obvious gastric irritation caused by oral administration of TP in rats