Correction to: Re­fracture and correlated risk factors in patients with osteoporotic vertebral fractures.

In the Original publication of the article, the funding ID has been incorrectly published as (815602390) in the Acknowledgements.

Re-fracture and correlated risk factors in patients with osteoporotic vertebral fractures.

Re-fracture risk is higher following osteoporotic fracture. However, there is no accurately reported rate of re-fracture incidence in southwest China. The purpose of this study was to describe the osteoporotic vertebral fracture (OVF) survival for re-fracture state and analyze the risk of re-fracture. This historical cohort study was conducted in four hospitals in southwest China. Patients aged ≥ 50 years (n = 586) with OVF who were supposed to receive anti-osteoporosis drugs after the fracture were included (2012-2017). Telephone follow-up and referring case files were used to estimate the survival for re-fracture and identify the determinants of re-fracture. A total of 555 patients completed the follow-up investigation. Overall, 285 patients experienced a re-fracture, and the longest follow-up investigation time was 72 months. The survival rates for re-fracture at 12 months, 24 months, 36 months, and 48 months were 82.0%, 71.5%, 61.7%, and 34.0%, respectively. The factors correlated with re-fracture hazard were advanced age [hazard ratio (HR) = 1.996], being female (HR = 1.342), smoking (HR = 1.435), history of hypertension (HR = 1.219) and diabetes (HR = 3.271), and persistence of taking anti-osteoporosis drugs after fracture [0-3 months, 4-6 months, 7-12 months, and more than 12 months (HR = 0.703)]. OVF patients with advanced age, who were female, smoked, had fracture with hypertension or diabetes, and who complied poorly with anti-osteoporosis drug treatment presented higher prevalence of re-fracture and low anti-osteoporosis adherence in southwest China. The management of anti-osteoporosis after fracture is necessary in this area.

Molecular Dynamics Simulations of the Oil-Detachment from the Hydroxylated Silica Surface: Effects of Surfactants, Electrostatic Interactions, and Water Flows on the Water Molecular Channel Formation.

The detachment process of an oil molecular layer situated above a horizontal substrate was often described by a three-stage process. In this mechanism, the penetration and diffusion of water molecules between the oil phase and the substrate was proposed to be a crucial step to aid in removal of oil layer/drops from substrate. In this work, the detachment process of a two-dimensional alkane molecule layer from a silica surface in aqueous surfactant solutions is studied by means of molecular dynamics (MD) simulations. By tuning the polarity of model silica surfaces, as well as considering the different types of surfactant molecules and the water flow effects, more details about the formation of water molecular channel and the expansion processes are elucidated. It is found that for both ionic and nonionic type surfactant solutions, the perturbation of surfactant molecules on the two-dimensional oil molecule layer facilitates the injection and diffusion of water molecules between the oil layer and silica substrate. However, the water channel formation and expansion speed is strongly affected by the substrate polarity and properties of surfactant molecules. First, only for the silica surface with relative stronger polarity, the formation of water molecular channel is observed. Second, the expansion speed of the water molecular channel upon the ionic surfactant (dodecyl trimethylammonium bromide, DTAB and sodium dodecyl benzenesulfonate, SDBS) flooding is more rapidly than the nonionic surfactant system (octylphenol polyoxyethylene(10) ether, OP-10). Third, the water flow speed may also affect the injection and diffusion of water molecules. These simulation results indicate that the water molecular channel formation process is affected by multiple factors. The synergistic effects of perturbation of surfactant molecules and the electrostatic interactions between silica substrate and water molecules are two key factors aiding in the injection and diffusion of water molecules and helpful for the oil detachment from silica substrate.

Molecular dynamics simulations of the self-organization of side-chain decorated polyaromatic conjugation molecules: phase separated lamellar and columnar structures and dispersion behaviors in toluene solvent.

The self-organization of five model side-chain decorated polyaromatic asphaltene molecules with or without toluene solvent was investigated by means of atomistic molecular dynamic (MD) simulations. It was found that the organizational structure of polycyclic asphaltene molecules is significantly affected by the position and length of side chains. In the present study, two types of phase-separated stacking configurations, including the phase separated lamellar structure (PSLS) and the phase separated columnar structure (PSCS), were found. The PSLS and PSCS were also maintained in the presence of a small amount of toluene additive (30% wt fraction). When adding excess toluene molecules, the asphaltene molecules formed highly dispersed nanoaggregates. The dynamic properties of the π-π stacking structures in the PSLS and PSCS, as well as the nanoaggregates, were probed. It was found that the number and size of alkyl side chains significantly impacted the size and number of π-π stacking structures in the aggregates. Through tracking the structural evolution of the nanoaggregates, a possible dissociation mechanism of nanoaggregates is also suggested.