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Metal-reducing bacteria play an important role in the release and mobilization of arsenic from sediments into groundwater. This study aimed to investigate the influence of nitrate on arsenic bio-release. Microcosm experiments consisting of high arsenic sediments and indigenous bacterium Bacillus sp. D2201 were conducted and the effects of nitrate on the mobilization of As/Fe determined. The results show arsenic release is triggered by iron reduction, which is regulated by nitrate. Increasing the nitrate concentration from 0 to 1 and 3 mM decreased Fe(III) reduction by 62.5% and 16.9% and decreased As(V) bio-release by 41.5% and 85.5%, respectively. Moreover, the results of step-wise Wenzel sequential extractions indicate nitrate addition prevents the transformation of poorly crystalline iron oxides to well crystalline iron oxides. Overall, nitrate appears to have a dual effect, inhibiting both iron reduction and arsenic release by incubation strain D2201. This study offers new insights regarding the biogeochemistry of arsenic in groundwater systems.

As one of the most widely used recommender systems, movie recommendation plays an important role in our life. However, the data sparsity problem severely hinders the effectiveness of personalized movie recommendation, which requires more rich content information to be utilized. Posters and still frames, which directly display the visual contents of movies, have significant influences on movie recommendation. They not only reveal rich knowledge for understanding movies but also useful for understanding user preferences. However, existing recommendation methods rarely consider aesthetic features, which tell how the movie looks and feels, extracted from these pictures for the movie recommendation. To this end, in this paper, we propose an aesthetic-aware unified visual content matrix factorization (called UVMF-AES) to integrate visual feature learning and recommendation into a unified framework. Specifically, we first integrate the convolutional neural network (CNN) features and aesthetic features into probabilistic matrix factorization. Then we establish a unified optimization framework with these features for the movie recommendation. The experimental results on two real-world datasets show that our proposed method UVMF-AES is significantly superior to the state-of-the-art methods on movie recommendation.

Next basket recommendation with consideration of user sequential shopping behaviors plays a significant role in E-commerce to improve the user experience and service quality. Recently, recurrent neural networks (RNNs), especially attention-based RNN, have been widely adopted in the next basket recommendation. However, existing fixed attention mechanisms are not designed to model the dynamic and diverse characteristics of user appetites. In this paper, we propose an inter-basket and intra-basket adaptive attention network (IIAAN) for the next basket recommendation. Specifically, the inter-basket adaptive attention acts on all historical user baskets to model user's diverse long-term preferences, while the intra-basket adaptive attention is designed to act on item-level in the most recent basket to model user's dynamic and different short-term preferences. Then, we further integrate inter-basket and intra-basket adaptive attentions together to improve recommendation effectiveness. Finally, we evaluate the proposed model IIAAN using three real-world datasets from various E-commerce platforms. Our experimental results show that our model IIAAN significantly outperforms the state-of-the-art approaches for the next basket recommendation.

Spark-assisted compression ignition (SACI) is a potential way to improve thermal efficiency for gasoline engine with a relatively low compression ratio. The dual-injection system and spark strategy are considered to be an effective approach to control the combustion of SACI engine. Polyoxymethylene dimethyl ethers (PODE) is a potential fuel for carbon neutral with high oxygen content and unique molecule structure. In this study, the transition of combustion modes with different equivalence ratio and effects of direct injection ratio on SACI combustion and emissions fueled with PODE/gasoline under different loads were investigated. The results showed that SACI combustion could be achieved with the compression ratio of 13 and the brake thermal efficiencies at 2 bar, 3 bar, and 4 bar under the dual-fuel SACI were increased by 49%, 29%, and 27%, respectively, compared with the gasoline spark ignition mode. The increase in direct injection ratio first shortened the combustion duration and then prolonged. An appropriate direct injection ratio was shown to control the combustion process to achieve high efficiency combustion, at which low total HC, CO, and PM emissions were achieved while the NOx emissions remained at a low level. [ABSTRACT FROM AUTHOR]

In order to understand the soot formation in Diesel engine, a turbulent jet flame is used to simulate the combustion in the cylinder. The experimental study is performed to investigate the evolution of soot morphology for the maturation of nascent particle in a turbulent lifted jet flame fueled by n-heptane/toluene mixtures. An ultrasonic atomizer is used to evenly spread the fuel droplets to acquire single primary particles. Transmission electron microscopy is used to study the morphology of the particle sampled from the flame at different heights. Small soot aggregates are acquired from all the samples. Particle maturation such as agglomeration is accelerated under a high temperature by comparing the particle morphology sampled on the centerline and the wings of the flame. The precursors of nascent particles are depicted as dark nucleation dispersed to semitransparent polycyclic aromatic hydrocarbons. The nanostructure of nascent particles transforms from an amorphous state to an onion structure with the maturation of particles. Surface growth initially dominates the maturation of nascent particles in the direction of outside to inside for single particles. Agglomeration begins to emerge with the increased probability of collision at the end of maturation. Surface growth and agglomeration increase the mean particle diameter as the flame height increases. The oxidability of particles that undergo surface growth and agglomeration notably increases. The structure of nascent particles is inclined to be ordered and the mean particle diameter decreases with oxidation dominating the combustion reaction. [ABSTRACT FROM AUTHOR]

BACKGROUND: Thymoma is an uncommon intrathoracic malignant tumor and has a long natural history, with overall survival (OS) in these patients lasting decades. It is uncertain whether the survival of a patient with thymoma is affected by their prior cancer history (PCH). Finding out the impact of PCH on thymoma survival has important implications for both decision-making and research. METHODS: The Surveillance, Epidemiology, and End Results database was queried for patients with thymoma diagnosed between 1975 and 2015. Kaplan-Meier methods and the Cox proportional hazards model were used to analyze OS across a variety of stages, ages, and treatment methods, in patients both with and without PCH. RESULTS: A total of 3604 patients with thymoma were identified, including 507 (14.1%) with a PCH. The 10-year survival rate of patients with a PCH (53.8%) was worse than that of those without a PCH (40.32%; 95% CI, 35.24%-45.33%; P < .0001). However, adjusted analyses showed that the impact of a PCH was heterogenous across ages and treatment methods. In subset analyses, PCH was associated with worse survival among patients who were treated with chemoradiotherapy (HR, 2.80; 95% CI, 1.51- 5.20; P = .001) and among those who were ≤ 65 years (HR, 1.33; 95% CI, 1.02-1.73; P = .036). CONCLUSIONS: PCH provides an inferior OS for patients with thymoma. However, it does not worsen the survival in some subgroups, and these patients with thymoma may be eligible for study. [ABSTRACT FROM AUTHOR]

Dual-fuel reactivity-controlled compression ignition (RCCI) combustion using port injection of a less reactive fuel and early-cycle direct injection

The gas-bearing Longmaxi Formation (Fm.) records a complex tectonic history in which variations in structural and burial history directly effect the hydrocarbon maturation process. Through analysis of the tectonic-burial history, hydrocarbon maturity, and EASY% R o numerical simulations we examine three areas representing the full spectrum of geological variability in the southern Sichuan Basin, the Changning area, the Luzhou area and the Zigong area (Zishen well-1). Following deposition of the Longmaxi Fm., all three areas underwent five major tectonic events of subsidence and uplift, showing an overall long-term oscillation of the basin. The Longmaxi Fm. has undergone three major heating stages, Caledonian- Hercynian orogenesis time, the high geothermal gradient field of Hercynian and Indosinian time (approximately 200–300 Ma), and the Yanshanian-Himalayan stage. The high geothermal gradient stage is associated with extensive Emeishan flood basalts or concealed basalts, which could have played an important role in hydrocarbon maturation. The maturation process can be divided into five stages: Caledonian, Hercyninan, Indosinian, Yanshanian, and Himalayan. In the Yanshan period, the highest heating temperature of organic matter exceeded 200 °C and the maturation level was more than 2.4%, producing large amounts of natural gas, which is the main accumulation period of shale gas in the Longmaxi Fm. Due to the large amount of hydrocarbon generated, a large number of micropores were formed from organic matter evolution, especially nanoscale pores, during the middle diagenesis stage. The Longmaxi Fm. shale gas accumulation process is divided into four periods: the source-reservoir-cap deposition period, the initial accumulation period, the main accumulation period, and the adjustment period. In the main accumulation period, pyrolysis gas was dominant, which was stored within the pores, diagenetic fractures, and structural fractures in adsorbed and free state ways, forming the basic pattern of the Longmaxi Fm. shale gas. The current burial depth and structural stability of the Longmaxi Fm. are critical to gas reservoir protection. [ABSTRACT FROM AUTHOR]