Explainable Recommendation: Theory and Applications

Although personalized recommendation has been investigated for decades, the wide adoption of Latent Factor Models (LFM) has made the explainability of recommendations a critical issue to both the research community and practical application of recommender systems. For example, in many practical systems the algorithm just provides a personalized item recommendation list to the users, without persuasive personalized explanation about why such an item is recommended while another is not. Unexplainable recommendations introduce negative effects to the trustworthiness of recommender systems, and thus affect the effectiveness of recommendation engines. In this work, we investigate explainable recommendation in aspects of data explainability, model explainability, and result explainability, and the main contributions are as follows: 1. Data Explainability: We propose Localized Matrix Factorization (LMF) framework based Bordered Block Diagonal Form (BBDF) matrices, and further applied this technique for parallelized matrix factorization. 2. Model Explainability: We propose Explicit Factor Models (EFM) based on phrase-level sentiment analysis, as well as dynamic user preference modeling based on time series analysis. In this work, we extract product features and user opinions towards different features from large-scale user textual reviews based on phrase-level sentiment analysis techniques, and introduce the EFM approach for explainable model learning and recommendation. 3. Economic Explainability: We propose the Total Surplus Maximization (TSM) framework for personalized recommendation, as well as the model specification in different types of online applications. Based on basic economic concepts, we provide the definitions of utility, cost, and surplus in the application scenario of Web services, and propose the general framework of web total surplus calculation and maximization.Comment: 169 pages, in Chinese, 3 main research chapter

Shearing and Mixing Performance of Ultrahigh-Molecular-Weight Hydrolyzed Polyacrylamide (HPAM) Solution in a Helixes Static Mixer

Static mixers have been widely used to dilute high viscosity, high-molecular-weight polymer mother liquor for polymer flooding, in which the mixing performance plays a critical role. In this work, a novel mixing configuration, named as Helixes static mixer, was proposed to reduce high viscosity degradation rate of polyacrylamide solution resulting from mechanical shear during mixing process. Computational fluid dynamics simulations along with experiments were performed to investigate the mixing process. Several criteria such as the intensity of segregation, mixing distance, pressure loss, and shear strain rate were used to evaluate the mixing and shear performance of static mixers. Compared to the SMX and Kenics static mixer, a longer mixing distance is needed for the Helixes static mixer to achieve an ideal mixture. A lower shear strain rate along with less viscosity degradation rate is obtained in flow field of Helixes static mixer. The spiral-lead and helical directions of mixing elements were optimized to improve mixing performance. Experimental results are in good agreement with the numerical simulations on the intensity of segregation. The viscosity degradation rate of HPAM solution which flows through Helixes static mixer is lower than that of SMX and Kenics static mixers

Ubiquitin carboxyl-terminal hydrolase isozyme L1/UCHL1 suppresses epithelial-mesenchymal transition and is under-expressed in cadmium-transformed human bronchial epithelial cells

Cadmium (Cd), a highly toxic heavy metal, is widespreadly distributed in the environment. Chronic exposure to Cd is associated with the development of several diseases including cancers. Over the decade, many researches have been carried on various models to examine the acute effects of Cd; yet, limited knowledge is known about the long-term Cd exposure, especially in the human lung cells. Previously, we showed that chronic Cd-exposed human bronchial epithelial BEAS-2B cells exhibited transformed cell properties, such as anchorage-independent growth, augmented cell migration, and epithelial–mesenchymal transition (EMT). To study these Cd-transformed cells more comprehensively, here, we further characterized their subproteomes. Overall, a total of 63 differentially expressed proteins between Cd-transformed and passage-matched control cells among the five subcellular fractions (cytoplasmic, membrane, nuclear-soluble, chromatin-bound, and cytoskeletal) were identified by mass spectrometric analysis and database searching. Interestingly, we found that the thiol protease ubiquitin carboxyl-terminal hydrolase isozyme L1 (UCHL1) is one of the severely downregulated proteins in the Cd-transformed cells. Notably, the EMT phenotype of Cd-transformed cells can be suppressed by forced ectopic expression of UCHL1, suggesting UCHL1 as a crucial modulator in the maintenance of the proper differentiation status in lung epithelial cells. Since EMT is considered as a critical step during malignant cell transformation, finding novel cellular targets that can antagonize this transition may lead to more efficient strategies to inhibit cancer development. Our data report for the first time that UCHL1 may play a function in the suppression of EMT in Cd-transformed human lung epithelial cells, indicating that UCHL1 might be a new therapeutic target for chronic Cd-induced carcinogenesis. [Figure not available: see fulltext.

Association between dietary fiber intake and incidence of depression and anxiety in patients with essential hypertension

(1) Background: Our previous study found that the dietary fiber supplement in patients with hypertension increased SCFA-producers, Bifidobacterium and Spirillum in the gut microbiota, which may be associated with improvement of depression and anxiety through the gut–brain axis. However, only a few studies have explored the association between dietary fiber intake (DFI) and the incidence of depression and anxiety in hypertensive patients. (2) Methods: A cross-sectional survey was conducted in one comprehensive hospital and one community clinic aimed at understanding the status of DFI and the association between DFI and incidences of depression and anxiety in hypertensive patients. Levels of DFI were obtained through a two-24 h diet recall. According to the levels of DFI from low to high, the participants were divided into Q1, Q2, Q3 and Q4 groups. The Reported Outcomes Measurement Information System short form v1.0-Depression 8b and Anxiety 8a were used to assess patients’ levels of depression and anxiety. (3) Results: A total of 459 hypertensive patients were recruited and the daily DFI was 10.4 g. The incidences of hypertension combined with depression and anxiety were 19.6% and 18.5%, respectively. Regression analysis showed statistically significant associations between DFI and depression (B = −0.346, p = 0.001) and anxiety score (B = −0.565, p < 0.001). In logistic regression, after the covariates were adjusted, DFI was associated with the incidence of depression in Q3 (OR 2.641, 95% CI 1.050–6.640) and with that of anxiety in Q1 (OR 2.757, 95% CI 1.035–7.346), compared with Q4. (4) Conclusions: A higher consumption of DF was a protective factor for depression and anxiety in hypertensive patients

Spontaneous regression of retinopathy of prematurity:incidence and predictive factors

AIM:To evaluate the incidence of spontaneous regression of changes in the retina and vitreous in active stage of retinopathy of prematurity(ROP) and identify the possible relative factors during the regression.METHODS: This was a retrospective, hospital-based study. The study consisted of 39 premature infants with mild ROP showed spontaneous regression (Group A) and 17 with severe ROP who had been treated before naturally involuting (Group B) from August 2008 through May 2011. Data on gender, single or multiple pregnancy, gestational age, birth weight, weight gain from birth to the sixth week of life, use of oxygen in mechanical ventilation, total duration of oxygen inhalation, surfactant given or not, need for and times of blood transfusion, 1,5,10-min Apgar score, presence of bacterial or fungal or combined infection, hyaline membrane disease (HMD), patent ductus arteriosus (PDA), duration of stay in the neonatal intensive care unit (NICU) and duration of ROP were recorded.RESULTS: The incidence of spontaneous regression of ROP with stage 1 was 86.7%, and with stage 2, stage 3 was 57.1%, 5.9%, respectively. With changes in zone Ⅲ regression was detected 100%, in zoneⅡ 46.2% and in zoneⅠ 0%. The mean duration of ROP in spontaneous regression group was 5.65±3.14 weeks, lower than that of the treated ROP group (7.34±4.33 weeks), but this difference was not statistically significant (P=0.201). GA, 1min Apgar score, 5min Apgar score, duration of NICU stay, postnatal age of initial screening and oxygen therapy longer than 10 days were significant predictive factors for the spontaneous regression of ROP (P＜0.05). Retinal hemorrhage was the only independent predictive factor the spontaneous regression of ROP (OR 0.030, 95%CI 0.001-0.775, P=0.035).CONCLUSION:This study showed most stage 1 and 2 ROP and changes in zone Ⅲ can spontaneously regression in the end. Retinal hemorrhage is weakly inversely associated with the spontaneous regression

The CDEX-1 1 kg Point-Contact Germanium Detector for Low Mass Dark Matter Searches

The CDEX Collaboration has been established for direct detection of light dark matter particles, using ultra-low energy threshold p-type point-contact germanium detectors, in China JinPing underground Laboratory (CJPL). The first 1 kg point-contact germanium detector with a sub-keV energy threshold has been tested in a passive shielding system located in CJPL. The outputs from both the point-contact p+ electrode and the outside n+ electrode make it possible to scan the lower energy range of less than 1 keV and at the same time to detect the higher energy range up to 3 MeV. The outputs from both p+ and n+ electrode may also provide a more powerful method for signal discrimination for dark matter experiment. Some key parameters, including energy resolution, dead time, decay times of internal X-rays, and system stability, have been tested and measured. The results show that the 1 kg point-contact germanium detector, together with its shielding system and electronics, can run smoothly with good performances. This detector system will be deployed for dark matter search experiments.Comment: 6 pages, 8 figure