Mechanistic insight on water dissociation on pristine low-index TiO2 surfaces from machine learning molecular dynamics simulations

Water adsorption and dissociation processes on pristine low-index TiO$_{2}$ interfaces are important but poorly understood outside the well-studied anatase (101) and rutile (110). To understand these, we construct three sets of machine learning potentials that are simultaneously applicable to various TiO$_{2}$ surfaces, based on three density-functional-theory approximations. Here we show the water dissociation free energies on seven pristine TiO$_{2}$ surfaces, and predict that anatase (100), anatase (110), rutile (001), and rutile (011) favor water dissociation, anatase (101) and rutile (100) have mostly molecular adsorption, while the simulations of rutile (110) sensitively depend on the slab thickness and molecular adsorption is preferred with thick slabs. Moreover, using an automated algorithm, we reveal that these surfaces follow different types of atomistic mechanisms for proton transfer and water dissociation: one-step, two-step, or both. These mechanisms can be rationalized based on the arrangements of water molecules on the different surfaces. Our finding thus demonstrates that the different pristine TiO$_{2}$ surfaces react with water in distinct ways, and cannot be represented using just the low-energy anatase (101) and rutile (110) surfaces

TG/HDL-C Ratio and ba-PWV in Patients with Essential Hypertension

BackgroundDyslipidemia is a major risk factor for cardiovascular disease. Triglyceride /high-density lipoprotein cholesterol (TG/HDL-C) ratio has been proved to be more effective in predicting cardiovascular events than a blood lipid index or low-density lipoprotein cholesterol (LDL-C) /HDL-C ratio. There are few clinical studies about TG/HDL-C ratio assessing arterial stiffness in hypertensive populations. Moreover, studies on the characteristics of ambulatory blood pressure parameters by TG/HDL-C ratio are also rare.ObjectiveTo explore the association of fasting TG/HDL-C ratio with brachial-ankle pulse wave velocity (ba-PWV) in essential hypertensive patients based on analyzing these patients' clinical features, ambulatory blood pressure and ba-PWV.MethodsA total of 439 essential hypertension patients (aged 18-80 years) were recruited from Hypertension Department, Beijing Anzhen Hospital, Capital Medical University from August 2014 to December 2015. Data were collected, including sex, age and medical history (diabetes history, hyperlipidemia history, smoking status, drinking status) , height, weight, BMI, serum creatinine, total cholesterol, TG, LDL-C, HDL-C, serum uric acid, fasting blood glucose, calculated TG/HDL-C ratio, 24 h ambulatory blood pressure parameters〔mean systolic blood pressure (SBP) , diastolic blood pressure (DBP) and heart rate in 24 h, in the daytime and at the nighttime, prevalence of nocturnal fall in SBP and DBP, and dipper blood pressure pattern〕 during hospitalization, and mean heart rate. Arterial stiffness was assessed by ba-PWV. The above-mentioned indicators were compared between lower (n=219) and higher quantile groups (n=220) divided by TG/HDL-C ratio. The influencing factors of ba-PWV were investigated by multiple linear regression analysis.Results(1) Higher quantile group had higher male proportion, higher prevalence of hyperlipidemia and smokers, higher mean BMI, serum creatinine, total cholesterol, TG, serum uric acid, and fasting blood glucose, as well as lower men age, and HDL-C than lower quantile group (P<0.05) . (2) Higher quantile group had higher mean 24-hour SBP and DBP, daytime SBP and DBP, nighttime SBP and DBP, nighttime heart rate and ba-PWV, and lower prevalence of nocturnal fall in SBP and DBP, and dippers than lower quantile group (P<0.05) . (3) Multiple linear regression analysis showed that, age〔β=12.35, 95%CI (10.307, 14.401) 〕, fasting blood glucose〔β=20.69, 95%CI (1.532, 39.854) 〕, TG/HDL-C ratio〔β=20.99, 95%CI (6.176, 35.810) 〕 and 24 hour mean SBP〔β=7.57, 95%CI (5.656, 9.493) 〕 were associated with ba-PWV (P<0.05) .ConclusionIn essential hypertension patients, elevated 24-hour SBP and DBP were found in those with higher TG/HDL-C ratio, and TG/HDL-C ratio may be independently associated with ba-PWV. Monitoring TG/HDL-C ratio helps early detection of arteriosclerosis and elevated blood pressure, promoting comprehensive management of cardiovascular risk factors

Spatial Features of Urban Expansion in Vietnam Based on Long-Term Nighttime Lights Data

As a developing country, Vietnam has experienced rapid economic development since the 21st century. It is therefore becoming increasingly important to understand its spatial pattern of urban expansion. However, the key challenge in this endeavor lies in the lack of national accounting data for the sub-administrative divisions of Vietnam at the national level, especially longitudinal data over a long time series. The nighttime lights (NTL) data can objectively reflect the scope and intensity of human development and construction in urban built-up areas, which can effectively support the empirical analysis of the urban expansion process in Vietnam. This paper uses the intercalibration model to correct and fit the long time series of DMSP/OLS and VIIRS/NPP NTL data. Based on this, the data for the urban built areas of Vietnam from 2000 to 2018 are further extracted. The results are as follows. (1) The main urban expansion in Vietnam is concentrated in the southern Mekong Delta and the northern Red River Delta, represented by Ho Chi Minh City and Hanoi City, respectively. (2) Vietnam’s urban NTL has significant high–high clustering characteristics in the north-south delta regions. The main urban expansion hotspots were concentrated around Ho Chi Minh City before 2012, the northern region represented by Hanoi City was gradually transformed into a critical area that gathering urban expansion hotspots after 2012. (3) The cities with significant influence and high coupling degree of industrialization and globalization on the urbanization of Vietnam are concentrated in Ho Chi Minh City, Hanoi, and some northern delta provinces, showing that the impact of industrialization and globalization on urbanization in Vietnam is still limited to some regions. In addition, the results show that the size of the population and the level of industrialization are the main drivers of urban expansion in Vietnam, while the level of foreign investment shows little significance. The results are helpful for promoting the application of long time series NTL data in urban expansion and for further analyzing the urban pattern changes in Vietnam and the influencing factors behind them

Experimental Investigation on the Mechanical Performance of Steel-ECC Composite Girders with Corrugated Webs under Negative Moment

In order to improve the cracking performance in the negative moment region of composite continuous girder bridges with corrugated webs, engineered cementitious composite (ECC) is used instead of conventional normal concrete (NC). Web and concrete types are used as the main research parameters in experiments. The test results indicate that steel-ECC specimens have a higher flexural load capacity and stiffness than steel-NC specimens. The cracks of steel-ECC specimens are characterised by small width and dense distribution. Nonlinear finite element models are established and verified by experimental results. The simulated load–displacement curves are similar to the experimental ones, and the models have a high degree of accuracy. The ECC slab strength, thickness and width are used as parameters for the investigation to analyse the effect of the ECC slab on the flexural bearing capacity of composite girders. Compared with the results of calculations according to the code, the bearing capacity obtained from the parametric analysis is higher. It suggests that the contribution of the ECC slab needs to be considered when calculating the bearing capacity of the steel-ECC composite girder with corrugated webs

Mechanistic insight on water dissociation on pristine low-index TiO2 surfaces from machine learning molecular dynamics simulations

Water adsorption and dissociation processes on pristine low-index TiO2 interfaces are important but poorly understood outside the well-studied anatase (101) and rutile (110). To understand these, we construct three sets of machine learning potentials that are simultaneously applicable to various TiO2 surfaces, based on three density-functional-theory approximations. Here we show the water dissociation free energies on seven pristine TiO2 surfaces, and predict that anatase (100), anatase (110), rutile (001), and rutile (011) favor water dissociation, anatase (101) and rutile (100) have mostly molecular adsorption, while the simulations of rutile (110) sensitively depend on the slab thickness and molecular adsorption is preferred with thick slabs. Moreover, using an automated algorithm, we reveal that these surfaces follow different types of atomistic mechanisms for proton transfer and water dissociation: one-step, two-step, or both. These mechanisms can be rationalized based on the arrangements of water molecules on the different surfaces. Our finding thus demonstrates that the different pristine TiO2 surfaces react with water in distinct ways, and cannot be represented using just the low-energy anatase (101) and rutile (110) surfaces

Mechanistic insight on water dissociation on pristine low-index TiO2 surfaces from machine learning molecular dynamics simulations.

Water adsorption and dissociation processes on pristine low-index TiO2 interfaces are important but poorly understood outside the well-studied anatase (101) and rutile (110). To understand these, we construct three sets of machine learning potentials that are simultaneously applicable to various TiO2 surfaces, based on three density-functional-theory approximations. Here we show the water dissociation free energies on seven pristine TiO2 surfaces, and predict that anatase (100), anatase (110), rutile (001), and rutile (011) favor water dissociation, anatase (101) and rutile (100) have mostly molecular adsorption, while the simulations of rutile (110) sensitively depend on the slab thickness and molecular adsorption is preferred with thick slabs. Moreover, using an automated algorithm, we reveal that these surfaces follow different types of atomistic mechanisms for proton transfer and water dissociation: one-step, two-step, or both. These mechanisms can be rationalized based on the arrangements of water molecules on the different surfaces. Our finding thus demonstrates that the different pristine TiO2 surfaces react with water in distinct ways, and cannot be represented using just the low-energy anatase (101) and rutile (110) surfaces