Simulation Investigation on the Structure and Its Influence on the Impinging Pressure of the Carbon Dioxide Jet.

An improved understanding of the mechanisms of SC-CO2 jet drilling technology is important for the application of this new technology. The flow field structure and dynamic fluctuation of SC-CO2 jets are the key factors affecting the jet erosion performance. To improve the erosion performance of the SC-CO2 jet, it is necessary to study the relationship between the different flow fields of the jet. In this study, a numerical simulation model for SC-CO2 jet drilling technology is established. Based on the modified real-gas model, the pressure distribution and flow field characteristics of the SC-CO2 jet were obtained by the simulation investigation, and the reliability of the model was verified. The results show that the flow field structure of a supercritical CO2 jet has typical compressible flow field characteristics. As the jet is fully expanded, its pressure fluctuation is slight and less affected by the distance between the nozzle and the wall. When the jet is in the state of under-expansion, the flow field structure characteristics have a significant impact on the pressure distribution and peak pressure. At the same time, when the distance is large, when nozzle pressure ratio = 5, the pressure ratio has a more significant impact on the flow field and the pressure peak and distribution. The pressure distribution of different flow fields should be fully considered in the application.

Greenhouse gas emissions from the wheat-maize cropping system under different tillage and crop residue management practices in the North China Plain.

With increasing attention being placed on mitigating global warming and achieving agricultural sustainable intensification, conservation agriculture practices have gradually been implemented in the North China Plain (NCP). However, there are still knowledge gaps on the effects of conservation practices on greenhouse gas (GHG) emissions in this area. In this study, a four-year field experiment was conducted from 2014 to 2018 to assess the effects of tillage and crop residue management practices on the emissions of nitrous oxide (N2O) and methane (CH4). Subsequently, crop yields, area-scaled and yield-scaled total non-carbon dioxide (CO2) GHG emissions were assessed. Our research found that no-till (NT) decreased N2O emissions by 22.6% compared with conventional tillage (CT) in winter wheat (Triticum aestivum L.) seasons, but there was no difference between tillage practices in summer maize (Zea mays L.) seasons. Crop residue retention practice (+R) increased N2O emissions by 28.1% and 26.7% compared with residue removal practice (-R) in winter wheat and summer maize seasons, respectively. The NT soils took up more CH4 compared with the CT soils in summer maize seasons. Area-scaled total non-CO2 GHG emissions showed trends similar to those of N2O emission. Since crop residue retention improved the maize yield compared with the residue removal treatments, yield-scaled total non-CO2 GHGs emission did not differ between residue management practices in summer maize seasons. Our four-year field measurements indicated that no-till practice could be more useful as an option to mitigate non-CO2 GHG emissions in the wheat - maize cropping system.

[Study on the Relationship between First-Time Complementary Feeding Practice and the Nutritional Status of Infants and Young Children in the Multi-Ethnic Rural Areas of Sichuan Province].

OBJECTIVE: To evaluate the current status of first food supplement and the nutrition of infants and young children in rural areas inhabited by people of Han, Tibetan, and Yi ethnicities in Sichuan Province, and to explore the relationship between the first ever feeding of food supplement and the nutritional status. METHODS: Using a multi-stage randomized cluster sampling method, we selected 2 Han counties, 2 Tibetan counties and 2 Yi counties in rural areas of Sichuan Province. These counties were previously defined as economically poor counties, but had since been lifted out of poverty. They were selected for this study before they came out of poverty. Infants and young children of 12-24 months old and their main caregivers from these counties were the subjects of the study. Structured questionnaires were used to collect information concerning the sociodemographic characteristics of infants and young children and their caregivers, and the first complementary feeding for infants and young children. Infant and young children weight scales and length/height tapes were used to collect the weight and length/height data of infants and young children. Unconditional logistic regression was used to analyze the correlation between the behavior of giving supplementary food for the first time to infants and young children and their nutritional status. RESULTS: A total of 1117 pairs of infants and children and their caregivers were investigated. Regarding the time of first supplementary food addition, nearly half of the caregivers in Han areas started adding supplementary food when the infants were 6 months old, accounting for 43.07% (171/397). Most of the caregivers in Yi and Tibetan areas started giving infants and young children supplementary food when they were less than 6 months old, accounting for 77.18% (301/390) and 47.58% (157/330), respectively. In terms of the types of supplementary food added for the first time, caregivers in Han areas mainly used homemade rice cereal, accounting for 41.56% (165/397), caregivers in Tibetan areas mainly used meat, vegetables or fruits and other complementary foods, accounting for 42.12% (139/330), and caregivers in Yi areas mainly used homemade rice cereal, accounting for 46.41% (181/390). The overall malnutrition rate of infants and young children was 28.83% (322/1117) and the malnutrition rate of infants and young children in Han, Tibetan, and Yi areas were 10.58% (42/397), 24.85 (82/330), and 50.77 (198/390), respectively. The regression analysis results show that after controlling for confounding factors, compared with Han areas, it is more likely for infants and young children in Yi areas to be malnourished ( OR=9.49, 95% CI 6.00-15.00). Compared with adding other types of complementary foods for the first time, infants and young children given iron-fortified rice cereal had a lower risk of malnutrition ( OR=0.54, 95% CI0.29-0.99). CONCLUSION: The multi-ethnic rural areas of Sichuan Province had problems that supplementary foods are added too early, and that the types of supplementary foods added for the first time were not appropriate. In addition, the nutritional status of local infants and young children in these areas was causing concerns. The malnutrition problem of infants and young children was especially prominent in the Yi ethnic areas. Adding iron-fortified rice cereal for the first time could reduce the possibility of malnutrition in infants and young children to a certain extent. It is recommended that attention should be given to the health education intervention of the first supplementary food for infants and young children to effectively improve the nutritional status of infants and young children in these areas.

[The Association Between Abdominal Obesity and Diabetes among Middle-aged and Older Adults with Normal BMI].

OBJECTIVE: To explore the relationship between abdominal obesity and diabetes among middle-aged and older adults with normal body mass index (BMI) and to provide reference information for formulating targeted diabetes prevention and control measures for this population. METHODS: Data were extracted from the China Health and Retirement Longitudinal Study (CHARLS) done in 2015. Middle-aged and older adults who were aged 45 and older and had normal BMI were included in the study. According to their status of diabetes, the subjects were divided into two groups, non-diabetes and diabetes groups. χ 2 test was used to investigate the difference between two groups. Logistic regression was used to do the multivariate analysis of factors influencing diabetes. RESULTS: A total of 5 197 middle-aged and older adults with normal BMI ranging between 18.5 and 24 kg/m 2 were included. The prevalence of diabetes was 11.26% (585/5 197) and the prevalence of abdominal obesity was 41.56% (2 160/5 197). Univariate analysis showed that the difference in age, residence, the status of hypertension, dyslipidemia and abdominal obesity between non-diabetic group and the diabetic group were statistically significant ( P<0.01). The prevalence of diabetes among adults with abdominal obesity was 14.2% (307/2 160) and that among people with no abdominal obesity was 9.2% (278/3 037). Compared with people with no abdominal obesity, the prevalence of diabetes among people with abdominal obesity was higher and the difference were statistically significant ( P<0.01). Multivariate logistic regression analysis showed that, among middle-aged and older adults with normal BMI, those with abdominal obesity, aged 60 years and older, living in urban areas, having hypertension and having dyslipidemia had higher probability of developing diabetes. CONCLUSION: Abdominal obesity and diabetes are becoming a serious problem among middle-aged and older adults with normal BMI and abdominal obesity may be related to higher risks of diabetes. It is recommended that more attention is given to abdominal obesity in this population to reduce the possibilities of diabetes.

Conosiligins A-D, Ring-Rearranged Tremulane Sesquiterpenoids from Conocybe siliginea.

Conosiligins A-D (1-4), four ring-rearranged sesquiterpenoids, were isolated from cultures of the basidiomycete Conocybe siliginea. Their structures and absolute configurations were determined by detailed spectroscopic analyses and equivalent circulating density (ECD) calculations. Compounds 1 and 2 possess a 5/8-fused ring system, while 3 has a 5/6-fused backbone conjugated with a γ-lactone. Compound 4 is a 5,6-seco tremulane derivative with the loss of a skeletal carbon, featuring a tetracyclic system involving a pyranone moiety. Compounds 3 and 4 inhibited Con A-induced T cell proliferation with IC50 values of 12.3 and 6.6 µM, respectively.

Dynamics in soil organic carbon of wheat-maize dominant cropping system in the North China Plain under tillage and residue management.

A site experiment was conducted to assess temporal dynamics of soil organic carbon (SOC) and the drivers under no-tillage (NT) and residue retention (RR) in the North China Plain (NCP). The results indicated that NT and RR can significantly increase SOC up to a depth of 30 cm. On average, NT increased SOC by 8.1-34.5% compared with PT, and RR increased SOC by 3.5-14.4% compared with R0 at 0-10 cm. Increases in SOC under NT or RR could be increased by 4-10 percentage points through the significantly positive interactions of NT and RR. Among the sources of SOC variations, tillage-induced variations accounted for 74.4 and 44.3% of the total variations in SOC at 0-5 cm for wheat and maize season, respectively. Experimental duration was also a significant source of variation. Stepwise regression indicated dynamics in SOC at 0-5 cm mainly due to the positive effects of precipitation, the negative effects of soil bulk density for the wheat season, the negative effects of radiation for the maize season, and antagonistic effects of temperature between wheat and maize season. Generally, positive effects of NT and RR on SOC were both confirmed, but fluctuations and variations induced by interactions of practices and seasonal climatic conditions were also significant in the NCP.

Construction of a circRNA-miRNA-mRNA network based on competitive endogenous RNA reveals the function of circRNAs in osteosarcoma.

BACKGROUND: Osteosarcoma (OS) is a common primary malignant bone tumour. Growing evidence suggests that circular RNAs (circRNAs) are closely related to the development of tumours. However, the function of circRNAs in OS remains unknown. Here, we aimed to determine the regulatory mechanisms of circRNAs in OS. METHODS: The expression profiles of OS circRNA (GSE96964), microRNA (GSE65071) and mRNA (GSE33382) were downloaded from the Gene Expression Omnibus (GEO) database to identify differentially expressed circRNAs, miRNAs and mRNAs in OS. A ceRNA network was constructed based on circRNA-miRNA pairs and miRNA-mRNA pairs. MRNAs with significant prognostic differences were identified by the TARGET database in the network. Functional and pathway enrichment analyses were performed, and interactions between proteins were predicted using Cytoscape. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were performed to elucidate the possible functions of these differentially expressed circRNAs. RESULTS: A total of 15 downregulated circRNAs, 136 upregulated miRNAs and 52 downregulated mRNAs were identified in OS. Finally, a circRNA-miRNA-mRNA network was constructed in OS based on 14 circRNAs, 24 miRNAs, and 52 mRNAs. GO and KEGG pathway analyses suggested that the mRNAs in the network may be involved in the pathogenesis and progression of OS. Four mRNAs identified by the TARGET database were significantly associated with OS survival prognosis. A circRNA-miRNA-mRNA subnetwork was constructed based on these four mRNAs. CONCLUSION: Our results provide a deeper understanding of the regulatory mechanisms by which circRNAs compete for endogenous RNAs in OS.

[Validation of vegetation coverage and NDVI based on UAV remote sensing method and its response to hydrothermal gradient]. / åŸºäºŽæ— äººæœºä½Žç©ºé¥æ„Ÿçš„è’æ¼ æ¤è¢«è¦†ç›–åº¦ä¸Žå½’ä¸€åŒ–æ¤è¢«æŒ‡æ•°éªŒè¯åŠå ¶å¯¹æ°´çƒ­æ¢¯åº¦çš„å“åº”.

To verify the accuracy of MODIS-NDVI data products in deserts and provide guidance for scientific management of desert grasslands in the context of climate change, we examined the responses of fractional vegetation cover (FVC) and normalized difference vegetation index (NDVI) to hydrothermal gradient in arid desert areas using unmanned aerial vehicle (UAV) remote sensing. In Alxa desert region of Inner Mongolia, GreenSeeker handheld spectrometer was used to obtain NDVI (NDVIR) of 100 sampling points. NDVI was extracted by MODIS-NDVI data products (NDVIM), and the accuracy of NDVIM was verified by NDVIR. FVC of each sampling point was obtained through unmanned aerial vehicle remote sensing (FVCU), which was used to examine the FVC that was retrieved by the pixel binary model (FVCM). In addition, combining meteorological data, we examined the responses of FVC and NDVI to hydrothermal gradient based on UAV remote sensing method. The results showed that MODIS-NDVI data products reflected the real NDVI in Alxa area with an accuracy of 84.2%, but NDVIM were 15.7% higher than the actual values. FVCM reflected the vegetation coverage of Alxa region with an accuracy of 83.1%, which were 14.8% lower than the real value. Effects of meteorological factors on NDVI was different, depending on the different acquisition methods. NDVI was affected not only by temperature and precipitation, but also by ground temperature, evaporation and the interaction between evaporation and ground temperature. Because of the different degree of atmospheric influence, NDVIM was more affected by ground temperature, evaporation and precipitation than NDVIR, while NDVIR was more affected by temperature than NDVIM. To examine the changes of vegetation coverage across hydrothermal gradient in desert area, we should consider not only precipitation and temperature, but also the interaction between evaporation, ground temperature and meteorological factors. The interaction between temperature and rainfall, evaporation and ground temperature, and between temperature and evaporation had greater impacts on FVCU.

Cytotoxic ergosterols from cultures of the basidiomycete Psathyrella candolleana.

Three newly isolated ergosterols, psathergosterols A-C (1-3), together with two known ones (4 and 5), have been isolated from cultures of the basdiomycete Psathyrella candolleana. Their structures with the absolute configuration were elucidated by means of spectroscopic methods and the single crystal X-ray diffraction. Compounds 2-4 exhibited certain cytotoxicities to five human cancer cell lines (HL-60, SMMC-7721, A-549, MCF-7, SW480).

Treadmill Exercise Reverses Depression Model-Induced Alteration of Dendritic Spines in the Brain Areas of Mood Circuit.

Depression is one of the most prevalent psychiatric disorders. Exercise has been shown to be effective in the amelioration of depression, but the underlying mechanism remains largely unknown. Alterations in the density and morphology of dendritic spines are associated with psychiatric diseases. Chronic unpredictable mild stress (CUMS) is an established animal model of depression. The aim of this study was to determine whether treadmill exercise reverses CUMS-induced both depression-like behaviors and alterations in spine density and morphology of the principal neurons in the brain areas of the mood circuits including the hippocampus, medial prefrontal cortex (mPFC), nucleus accumbens (NAc) and basolateral amygdala (BLA). Male rats were randomly divided into four groups: control, CUMS, exercise, and CUMS+exercise. CUMS-induced depression-like behaviors were evaluated by the sucrose preference test (SPT). Golgi staining was used to visualize dendritic spines. Our results showed that CUMS-induced depression-like behaviors characterized by a decrease in sucrose consumption were accompanied by a decrease in spine density and a change in spine morphology in the pyramidal neurons of both the hippocampal CA3 area and the mPFC, and an increase in spine density and an alteration in spine shape in both the NAc medium spiny neurons (MSNs) and the BLA neurons; exercise reversed both CUMS-induced depression-like behaviors and alterations in dendritic spines. This study provides important information for understanding the mechanism through which exercise ameliorates CUMS-induced depression-like behaviors.

Management-induced greenhouse gases emission mitigation in global rice production.

Mitigating greenhouse gases (GHGs) emissions from rice paddy (Oryza sativa L.) and balancing the trade-offs between reducing emission and sustaining food security have raised global concerns. A global meta-analysis of rice experimental data was conducted to assess changes in emissions of GHGs (CH4 and N2O) and global warming potential (GWP) in response to improvements through 12 field management practices. The results indicated that changes in GWP were mainly attributed to CH4 emission even though N2O emission was significantly affected by conversion of field management practices. Specifically, GWP per unit rice plant area (area-scaled) was significantly increased by 20.1%, 66.2%, and 84.5% with nitrogen (N) fertilizer input, manuring, and residue retention (P < 0.05), along with significant increments in area-scaled CH4 emission under the above management practices by 8.9%, 60.4%, and 91.8%, respectively (P < 0.05). Due to the significant increase in rice yield, a decreasing trend for GWP per unit rice yield (yield-scaled) was observed with N fertilizer input. In addition, CH4 and GWP decreased significantly at both area- and yield-scale under non-flooding irrigation but with a reduction in rice yield by 3.3% (P < 0.05). Improvement in rice variety significantly enhanced crop yield by 15.3% while reducing area-scaled GWP by 27.7% (P < 0.05). Furthermore, other management practices, such as application of herbicides, biochar, and amendments (non-fertilizer materials) reduced yield-scaled GWP while increasing rice yield. Thus, changes in field management practices have the potential to balance the trade-offs between high yield and low emission of GHGs. However, in-depth studies are needed to determine the interactions between field management practices and site-specific soil/climate conditions.

Two highly oxygenated Ergosterols from cultures of the Basidiomycete Conocybe siliginea.

Two highly oxygenated ergosterols, (22E,24R)-3ß,5α,6ß,9α,14α,25-hexhydroxyergosta-7,22-diene (1), and (22E,24R)-3ß,5α,6ß,14α,25-pentahydroxyergosta-7,9(11),22-triene (2), together with two known ones, have been isolated from cultures of the basidiomycete Conocybe siliginea. Their structures were elucidated on the basis of extensive spectroscopic means. Two new compounds (1 and 2) were tested for their nitric oxide synthase inhibitory activities. However, none of them showed any activity (IC50 > 40 µM).

Visible-Light Photocatalytic Synthesis of Amines from Imines via Transfer Hydrogenation Using Quantum Dots as Catalysts.

CdSe/CdS core/shell quantum dots (QDs) can be used as stable and highly active photoredox catalysts for efficient transfer hydrogenation of imines to amines with thiophenol as a hydrogen atom donor. This reaction proceeds via a proton-coupled electron transfer (PCET) from the QDs conduction band to the protonated imine followed by hydrogen atom transfer from the thiophenol to the α-aminoalkyl radical. This precious metal free transformation is easy to scale up and can be carried out by a one-pot protocol directly from aldehyde, amine, and thiophenol.  Additional advantageous features of this protocol include a wide substrate scope, high yield of the amine products, extremely low catalyst loading (0.001 mol %), high turnover number (105), and the mild reaction conditions of using visible light or sun light at room temperature in neutral media.

[Effects of tillage practices on photosynthetic performance diurnal variation during filling stage and grain yield of winter wheat]. / è€•ä½œæ–¹å¼å¯¹å†¬å°éº¦çŒæµ†æœŸå ‰åˆæ€§èƒ½æ—¥å˜åŒ–å’Œç±½ç²’äº§é‡çš„å½±å“.

Photosynthesis characteristics of winter wheat under different tillage practices during fil-ling stage are vital for dry matter accumulation, transfer, and yield development. A field experiment, including no-till with residue removal (NT), no-till with residue retention (NTS), rotary tillage with residue removal (RT), rotary tillage with residue retained (RTS), subsoiling with residue removal (DT), subsoiling with residue retained (DTS), plow tillage with residue removal (CT), and plow tillage with residue retained (CTS) was conducted at Wuqiao experimental station of China Agricultural University since October 2008. The diurnal variation of photosynthetic characteristics of flag leaf, photosynthetic response curve, and crop yield under different tillage practices were evaluated during winter wheat filing stage in this study. The results showed thatthe net photosynthetic rate and stomatal conductance of flag leaf both diurnally varied with the bimodal curve, and the net photosynthetic rates were higher under treatments with residue retained than those under with residue removal. Diurnal variation of intercellular carbon dioxide concentration was observed with a "V-shaped wide mouth" bimodal curve under all treatments. Daily transpiration rate exhibited "double peak curve", except for the "single peak curve" under DTS, RTS and RT. The stimulated net photosynthetic rate was increased by 20.0%, 21.7%, 19.7%, 21.5%, 0.8%, 12.1% and 4.2% under NT, DT, RT, CT, CTS, RTS, and CTS, compared with DTS, respectively. Photosynthetic response curves were fitted better under treatments with residue retained than under treatments with residue removal. As for crop grain yields, the highest one was observed under DTS, following by RTS and CTS, and the lowest under CT. Crop grain yield was increased by 10.8%, 1.3%, 2.1%, 5.4%, 11.9%, 12.4%, and 12.6% under DTS, compared with NTS, RTS, CTS, NT, DT, RT, and CT, respectively. Thus, residue retaining under different tillage practices (e.g. NTS and DTS) could mitigate the mid-day depression of photosynthesis, maintain a high photosynthetic rate of winter wheat, and improve the dry matter accumulation and crop production.

A hospital-based survey of patients with severe valvular heart disease in China.

OBJECTIVES: Due to increasing aging, the epidemiology of VHD may have changed in China. This study aimed to provide contemporary information on the prevalence, distribution patterns, and etiology of severe VHD in China. METHODS: This was a retrospective survey at Second Affiliated Hospital of Zhejiang University, which included all consecutive patients between 2010 and 2015. RESULTS: In all, 139,496 patients were enrolled. Among severe valve diseases, MR was the most frequent (n=946, 0.68%) followed by MS (n=524, 0.38%), AS (n=392, 0.28%), and AR (n=371, 0.27%). Severe MR and AS prevalence rates increased strikingly with age. Rheumatic heart disease had an prevalence of 1.56% (n=2179), and remained one of the most common causes of severe VHD in patients younger than 65years old (99.5% of MS with rheumatic; 27.6% of MR with rheumatic; 25.7% of AS with rheumatic; 31.6% of AR with rheumatic). Aortic valve calcification was the predominant AS etiology, and its prevalence greatly increased with age. In severe AR, rheumatic fever was the most common etiology in patients below 65; in those above 65, etiology was mostly degenerative. In severe primary MR, mitral valve prolapse was the most common cause. Prevalence of secondary MR increased with age, from 16.4% in 18-44years old to 51.7% in individuals ≥75. CONCLUSIONS: Severe valvular diseases are very common; rheumatic fever and degenerative valvular changes remain predominant causes in patients below 65 and older ones, respectively. Young adults present mainly with primary MR, while secondary MR is more common in elderly ones.

Association between Pax8-PPARandgamma;1 Rearrangement and Follicular Thyroid Cancer: a Meta-Analysis.

BACKGROUND: Pax8 and peroxisome proliferator-activated receptor gamma 1 gene (Pax8-PPARγ1) are important factors in tumors. Several studies have suggested that follicular thyroid cancer may arise from Pax8- PPArγ1 rearrangement. In order to have a better understanding of the association between Pax8-PPARγ1 rearrangement and follicular thyroid cancer, we conducted the presenmt meta-analysis. MATERIALS AND METHODS: The information was extracted from PubMed, EMBASE and Web of Science. Statistic analysis was performed with Stata12.0 software. Odds ratios (ORs) were calculated using a fixed-effects model. We also performed heterogeneity and publication bias analyses. RESULTS: Nine studies including 198 follicular thyroid cancer patients and 268 controls were considered eligible. The frequency of Pax8-PPARγ1 rearrangement was significantly higher in the follicular thyroid cancer group than in the control group, with a pooled OR of 6.63 (95%CI=3.50-12.7). In addition, through subgroup analysis, the OR between Pax8-PPARγ1 rearrangement and follicular thyroid cancer was 6.04 (95%CI = 3.18-11.5) when using benign tumor tissues as controls. The OR for the method subgroup was 9.99 (95% CI =4.86-20.5) in the RT-PCR. CONCLUSIONS: The final results demonstrated that Pax8-PPARγ1 rearrangement has significant association with follicular thyroid cancer.

Load partitioning between the bcc-iron matrix and NiAl-type precipitates in a ferritic alloy on multiple length scales.

An understanding of load sharing among constituent phases aids in designing mechanical properties of multiphase materials. Here we investigate load partitioning between the body-centered-cubic iron matrix and NiAl-type precipitates in a ferritic alloy during uniaxial tensile tests at 364 and 506 °C on multiple length scales by in situ neutron diffraction and crystal plasticity finite element modeling. Our findings show that the macroscopic load-transfer efficiency is not as high as that predicted by the Eshelby model; moreover, it depends on the matrix strain-hardening behavior. We explain the grain-level anisotropic load-partitioning behavior by considering the plastic anisotropy of the matrix and elastic anisotropy of precipitates. We further demonstrate that the partitioned load on NiAl-type precipitates relaxes at 506 °C, most likely through thermally-activated dislocation rearrangement on the microscopic scale. The study contributes to further understanding of load-partitioning characteristics in multiphase materials.

Methane and nitrous oxide emissions under no-till farming in China: a meta-analysis.

No-till (NT) practices are among promising options toward adaptation and mitigation of climate change. However, the mitigation effectiveness of NT depends not only on its carbon sequestration potential but also on soil-derived CH4 and N2O emissions. A meta-analysis was conducted, using a dataset involving 136 comparisons from 39 studies in China, to identify site-specific factors which influence CH4 emission, CH4 uptake, and N2O emission under NT. Comparative treatments involved NT without residue retention (NT0), NT with residue retention (NTR), compared to plow tillage (PT) with residue removed (PT0). Overall, NT0 significantly decreased CH4 emission by ~30% (P < 0.05) compared to PT0 with an average emission 218.8 kg ha(-1) for rice paddies. However, the increase in N2O emission could partly offset the benefits of the decrease in CH4 emission under NT compared to PT0. NTR significantly enhanced N2O emission by 82.1%, 25.5%, and 20.8% (P < 0.05) compared to PT0 for rice paddies, acid soils, and the first 5 years of the experiments, respectively. The results from categorical meta-analysis indicated that the higher N2O emission could be mitigated by adopting NT within alkaline soils, for long-term duration, and with less N fertilization input when compared to PT0. In addition, the natural log (lnR) of response ratio of CH4 and N2O emissions under NT correlated positively (enhancing emission) with climate factors (temperature and precipitation) and negatively (reducing emission) with experimental duration, suggesting that avoiding excess soil wetness and using NT for a long term could enhance the benefits of NT. Therefore, a thorough understanding of the conditions favoring greenhouse gas(es) reductions is essential to achieving climate change mitigation and advancing food security in China.

A Zr-based bulk metallic glass for future stent applications: Materials properties, finite element modeling, and in vitro human vascular cell response.

Despite the prevalent use of crystalline alloys in current vascular stent technology, new biomaterials are being actively sought after to improve stent performance. In this study, we demonstrated the potential of a Zr-Al-Fe-Cu bulk metallic glass (BMG) to serve as a candidate stent material. The mechanical properties of the Zr-based BMG, determined under both static and cyclic loadings, were characterized by high strength, which would allow for the design of thinner stent struts to improve stent biocompatibility. Finite element analysis further complemented the experimental results and revealed that a stent made of the Zr-based BMG was more compliant with the beats of a blood vessel, compared with medical 316L stainless steel. The Zr-based BMG was found to be corrosion resistant in a simulated body environment, owing to the presence of a highly stable ZrO2-rich surface passive film. Application-specific biocompatibility studies were conducted using human aortic endothelial cells and smooth muscle cells. The Zr-Al-Fe-Cu BMG was found to support stronger adhesion and faster coverage of endothelial cells and slower growth of smooth muscle cells than 316L stainless steel. These results suggest that the Zr-based BMG could promote re-endothelialization and potentially lower the risk of restenosis, which are critical to improve vascular stent implantation integration. In general, findings in this study raised the curtain for the potential application of BMGs as future candidates for stent applications. STATEMENT OF SIGNIFICANCE: Vascular stents are medical devices typically used to restore the lumen of narrowed or clogged blood vessel. Despite the clinical success of metallic materials in stent-assisted angioplasty, post-surgery complications persist due to the mechanical failures, corrosion, and in-stent restenosis of current stents. To overcome these hurdles, strategies including new designs and surface functionalization have been exercised. In addition, the development of new materials with higher performance and biocompatibility can intrinsically reduce stent failure rates. The present study demonstrates the advantages of a novel material, named bulk metallic glass (BMG), over the benchmarked 316L stainless steel through experimental methods and computational simulations. It raises the curtain of new research endeavors on BMGs as competitive alternatives for stent applications.