Cerium doped copper/ZSM-5 catalysts used for the selective catalytic reduction of nitrogen oxide with ammonia

The CuCe/ZSM-5 catalysts with different cerium loadings (0, 0.5, 1.0, 1.5 and 2.0wt.%) was investigated to evaluate the correlation between structural characteristics and catalytic performance for the selective catalytic reduction (SCR) of NO by NH3. It was found that the addition of cerium increased copper dispersion and prevented its crystallization. According to the results of X-ray photoelectron spectroscopy (XPS) and temperature-programmed reduction by hydrogen (H2-TPR), copper species were enriched on the ZSM-5 grain surfaces and part of copper ions was incorporated into the cerium lattice. Addition of cerium improved the redox properties of the CuCe/ZSM-5 catalysts, owing to the higher valence of copper and mobility of lattice oxygen than those of Cu/ZSM-5 catalyst. Hence the introduction of cerium in Cu/ZSM-5 improved significantly NO conversion. On the one hand, the cerium introduction into Cu-Z enhances their low-temperature activities. 95% NO conversion is reached around 197°C for Cu-Z while the corresponding temperature value decreases to 148°C for CuCe4-Z. On the other hand, the temperature range of efficient NO reduction (95%) also extends to higher temperature when the cerium are added to Cu/ZSM-5. Among the Cu-Ce/ZSM-5 catalysts tested, the CuCe4-Z sample exhibits the highest catalytic activity with the temperature range for 90% NO removal of 148-427°C

A Calculation Method For Mineral Reserves Based On Multi-point Geostatistics

To improve the accuracy of the calculation for the current mineral resource reserves, a calculation method for mineral resource reserves based on multi-point geostatistics was proposed. The new method, including four major steps, focuses on calculating resource reserves of ore body accurately for rational development and utilization of mineral resources. To represent the spatial geometric relationship of the ore body accurately, a three-dimensional irregular tetrahedron voxel (3D ITV) model construction method for the ore body is proposed first. Second, a tetrahedron voxel grade model built by the mineral reservation calculation oriented multi-point geostatistics method is proposed. The construction of 3D training image, definition of data template with N-order adjacency voxels, construction of search trees and conditional probability extraction of data event are conducted in this step. Finally, the resource reserves of the ore body are calculated on the basis of the tetrahedron voxel grade model. A calculation experiment of copper reserves is conducted to demonstrate the validity of the new method. The new method can be meaningful to the exploration, development, and utilization of mineral resources

Ghrelin attenuates avascular necrosis of the femoral head induced by steroids in rabbits

Purpose: Ghrelin is an endogenous ligand for growth hormone secretagogue receptor. The current study was aimed at examining the effect of ghrelin on avascular necrosis of the femoral head (ANFH) induced by steroids in a rabbit model and also exploring the underlying mechanism. Methods: Experimental rabbits were separated into three groups: Control, Vehicle and Ghrelin. We established a steroid-induced ANFH model in rabbits. Then, MRI scanning and hematoxylin-eosin staining (HE) were conducted to see ANFH. The mRNA levels of Vascular Endothelial Growth Factor (VEGF) and Bone Morphogenetic Protein 2 (BMP-2) were evaluated using real-time qRT-PCR. Results: Rabbits in the Vehicle group showed increased empty bone lacunae, reduced bone trabecula in femoral head; the number of hematopoietic cells in the bone marrow was reduced, whereas number of adipocytes increased with evident fusion phenomenon in comparison with the Control group. All of the changes induced in Vehicle group were attenuated in Ghrelin group. MRI scanning showed obvious necrosis of femoral head in the Vehicle group and less in the Ghrelin group. The mRNA levels of VEGF and BMP-2 were raised in Vehicle group and further enhanced in Ghrelin group. Conclusion: Ghrelin attenuates steroid-induced avascular necrosis in femoral head in rabbit model. A possible mechanism may be through VEGF/BMP-2 axis. Keywords: ANFH, BMP-2, Ghrelin, VEG

Large-scale effective connectivity analysis reveals the existence of two mutual inhibitory systems in patients with major depression

It is posited that cognitive and affective dysfunction in patients with major depression disorder (MDD) may be caused by dysfunctional signal propagation in the brain. By leveraging dynamic causal modeling, we investigated large-scale directed signal propagation (effective connectivity) among distributed large-scale brain networks with 43 MDD patients and 56 healthy controls. The results revealed the existence of two mutual inhibitory systems: the anterior default mode network, auditory network, sensorimotor network, salience network and visual networks formed an “emotional” brain, while the posterior default mode network, central executive networks, cerebellum and dorsal attention network formed a “rational brain”. These two networks exhibited excitatory intra-system connectivity and inhibitory inter-system connectivity. Patients were characterized by potentiated intra-system connections within the “emotional/sensory brain”, as well as over-inhibition of the “rational brain” by the “emotional/sensory brain”. The hierarchical architecture of the large-scale effective connectivity networks was then analyzed using a PageRank algorithm which revealed a shift of the controlling role of the “rational brain” to the “emotional/sensory brain” in the patients. These findings inform basic organization of distributed large-scale brain networks and furnish a better characterization of the neural mechanisms of depression, which may facilitate effective treatment

Interpreting core-level spectra of oxidizing phosphorene: Theory and experiment

We combine ab initio density functional theory calculations with the equivalent cores approximation to determine core-level binding-energy shifts at phosphorus sites caused by oxidation of phosphorene. We find that presence of oxygen increases the core-level binding energies of P atoms and expect binding-energy shifts of up to 6 eV in highly defective geometries. We have identified likely binding geometries of oxygen that help to interpret the observed core-level photoemission spectra in samples at different stages of oxidation and allow us to determine the fractions of specific local geometries

Maternal Prepregnancy Body Mass Index and Gestational Weight Gain on Pregnancy Outcomes

Objective: The aim of the present study was to evaluate the single and joint associations of maternal prepregnancy body mass index (BMI) and gestational weight gain (GWG) with pregnancy outcomes in Tianjin, China. Methods: Between June 2009 and May 2011, health care records of 33,973 pregnant women were collected and their children were measured for birth weight and birth length. The independent and joint associations of prepregnancy BMI and GWG based on the Institute of Medicine (IOM) guidelines with the risks of pregnancy and neonatal outcomes were examined by using Logistic Regression. Results: After adjustment for all confounding factors, maternal prepregnancy BMI was positively associated with risks of gestational diabetes mellitus (GDM), pregnancy-induced hypertension, caesarean delivery, preterm delivery, large-for-gestational age infant (LGA), and macrosomia, and inversely associated with risks of small-for-gestational age infant (SGA) and low birth weight. Maternal excessive GWG was associated with increased risks of pregnancy-induced hypertension, caesarean delivery, LGA, and macrosomia, and decreased risks of preterm delivery, SGA, and low birth weight. Maternal inadequate GWG was associated with increased risks of preterm delivery and SGA, and decreased risks of LGA and macrosomia, compared with maternal adequate GWG. Women with both prepregnancy obesity and excessive GWG had 2.2–5.9 folds higher risks of GDM, pregnancy-induced hypertension, caesarean delivery, LGA, and macrosomia compared with women with normal prepregnancy BMI and adequate GWG. Conclusions: Maternal prepregnancy obesity and excessive GWG were associated with greater risks of pregnancy-induced hypertension, caesarean delivery, and greater infant size at birth. Health care providers should inform women to start the pregnancy with a BMI in the normal weight category and limit their GWG to the range specified for their prepregnancy BMI

Risk and ambiguity of COVID-19 inhibit intentions for post-pandemic travel via reduced valuation of tourism

Purpose – This study aims to examine how the initial ambiguity of COVID-19 contributed to tourists' intentions for visiting a once-viral outbreak site in the future. Design/methodology/approach – The present study (N = 248) used partial least-squares structural equation modeling (PLS-SEM) to examine whether perceptions of ambiguity and mismanagement of COVID-19 are indirectly related to intentions to travel to Wuhan in a post-pandemic world through perceptions of risk and tourism value. Further, whether the model effects differed as a function of individual safety orientation was examined. Findings – Perceptions of COVID-19 risk and tourism value serially mediated the effects of perceived COVID-19 ambiguity on post-pandemic travel intentions. Safety orientation did not moderate any paths. Perceived risk was a negative direct correlate of post-pandemic travel intentions. Originality/value – The current study's strength is rooted in its specific targeting of post-pandemic travel intentions to Wuhan—the first city to experience a widescale outbreak of COVID-19 and subsequent international stigma—compared to general travel inclinations

A new 200‐year spatial reconstruction of West Antarctic surface mass balance

High‐spatial resolution surface mass balance (SMB) over the West Antarctic Ice Sheet (WAIS) spanning 1800‐2010 is reconstructed by means of ice core records combined with the outputs of the European Centre for Medium‐range Weather Forecasts “Interim” reanalysis (ERA‐Interim) and the latest polar version of the Regional Atmospheric Climate Model (RACMO2.3p2). The reconstruction reveals a significant negative trend (‐1.9 ± 2.2 Gt yr‐1 decade‐1) in the SMB over the entire WAIS during the 19th century, but a statistically significant positive trend of 5.4 ± 2.9 Gt yr‐1 decade‐1 between 1900 and 2010, in contrast to insignificant WAIS SMB changes during the 20th century reported earlier. At regional scales, the Antarctic Peninsula (AP) and western WAIS show opposite SMB trends, with different signs in the 19th and 20th centuries. The annual resolution reconstruction allows us to examine the relationships between SMB and large‐scale atmospheric oscillations. Although SMB over the AP and western WAIS correlates significantly with the Southern Annular Mode (SAM) due to the influence of the Amundsen Sea Low (ASL) and El Niño/Southern Oscillation (ENSO) during 1800‐2010, the significant correlations are temporally unstable, associated with the phase of SAM, ENSO and the Pacific decadal oscillation (PDO). In addition, the two climate modes seem to contribute little to variability in SMB over the whole WAIS on decadal‐centennial time scales. This new reconstruction also serves to identify unreliable precipitation trends in ERA‐Interim, and thus has potential for assessing the skill of other reanalyses or climate models to capture precipitation trends and variability