Preparation of Core-Shell Silver Nanoparticles@Mesoporous Silica Nanospheres with Catalytic Activities.

Core-shell silver nanoparticles@mesoporous silica spherical nanoparticles (Ag NPs@MSNs) were prepared by a two-step method. First, Ag NPs were synthesized by chemical reduction using silver nitrate (AgNO3) as the precursor, cetyl trimethyl ammonium bromide (CTAB) as the stabilizer, and sodium borohydride (NaBH4) as the reductant. Then, MSNs were obtained by employing CTABstabilized Ag NPs as the template and hydrolyzing tetraethoxysilane (TEOS) precursor in the presence of the alkaline precipitant, triethanolamine (TEOA). The effects of different preparation routes (core-first vs. shell-first), type of reductants as well as extraction methods and agents were studied. The obtained core-shell NPs were characterized by infrared spectroscopy (IR) and transmission electron microscopy (TEM). Our results showed that the core-first route was viable to produce uniform Ag NPs@MSNs with ordered mesostructures. Afterwards, those NPs were used as the catalyst to catalyze the reduction of rhodamine, a model dye compound representing organic pollutants in waste water, in the presence of NaBH4. It was found that Ag NPs@MSNs not only were efficient catalysts but also participated as coreductants in the reaction. Moreover, they exhibited almost no loss of catalytic efficacy after several reduction cycles, which indicated their promising future use as efficient recyclable catalysts for organic pollutant treatments.

USP14 promotes colorectal cancer progression by targeting JNK for stabilization.

MAPK/JNK signaling is pivotal in carcinogenesis. However, ubiquitin-mediated homeostasis of JNK remains to be verified. Here, with results from RNA sequencing (RNA-seq) and luciferase reporter pathway identification, we show that USP14 orchestrates MAPK/JNK signaling and identify USP14 as a deubiquitinase that interacts and stabilizes JNK. USP14 is elevated in colorectal cancer patients and is positively associated with JNK protein and downstream gene expression. USP14 ablation reduces cancer cell proliferation in vitro and colorectal tumorigenesis in vivo by downregulating MAPK/JNK pathway activation. Moreover, USP14 expression is induced by TNF-α, forming a feedback loop with JNK and leading to tumor amplification. Our study suggests that elevated expression of USP14 promotes MAPK/JNK signaling by stabilizing JNK, which in turn augments colorectal carcinogenesis, indicating a potential therapeutic target for colorectal cancer patients with increased USP14 expression.

Lagged settlement in sandy cobble strata and earth pressure on shield tunnel.

Lagged settlement is a typical accident induced by shield construction in sandy cobble strata. This paper analyzed the process and mechanism of lagged settlement, results show that all phases are in accord with the characteristics of ellipsoid theory of particle flows. Based on this theory, a method for calculating coefficient of lateral earth pressure and loosened earth pressure is proposed in this research. For the coefficient of lateral earth pressure, the boundary of loosened ellipsoid is divided into two parts, the arch zone and the excavation zone, and the lateral pressure coefficients are derived respectively according to the stress state. For loosened earth pressure on tunnel, the Terzaghi earth pressure theory and Protodyakonov earth pressure theory are adapted in different conditions according to the state of loosened cobble soil. Theories developed in this study can be applied on determination of shield excavation parameters, as well as calculation of loosened earth pressure and control of tunnel support.

Equivalent deformation modulus of sandy pebble soil-Mathematical derivation and numerical simulation.

This study aims to investigate the mechanical properties of sandy pebble soil through theoretical deduction and finite element analysis. Based on the assumption of stress uniformity or strain uniformity, the analytical formulas for calculating the equivalent deformation modulus of pebble soil are derived through RVEs. To verify the accuracy of the formulas, a series of numerical experiments are conducted through ABAQUS. Results show that theoretical calculation values match numerical simulation results well and the analytical formulas are effective when the pebble content is 0-60%. For pebble content lower than 20%, the equivalent deformation modulus could be described by "Stress Uniformity Model". When content is 20%-60%, pebble soil is a transition state from "Stress Uniformity" to "Strain Uniformity", for which the constitutive model could be expressed as a modified transition formula. This research is helpful for further investigation of mechanical properties of pebble soil. The theories developed in this study can be used in determining shield excavation parameters, and predicting the ground settlement caused by shield excavation.