Publications by authors named "Junfeng Wang"

529 Publications

Log-periodic quantum magneto-oscillations and discrete-scale invariance in topological material HfTe.

Natl Sci Rev 2019 Oct 6;6(5):914-920. Epub 2019 Aug 6.

International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China.

Discrete-scale invariance (DSI) is a phenomenon featuring intriguing log-periodicity that can be rarely observed in quantum systems. Here, we report the log-periodic quantum oscillations in the longitudinal magnetoresistivity ( ) and the Hall traces ( ) of HfTe crystals, which reveal the DSI in the transport-coefficients matrix. The oscillations in and show the consistent log-periodicity with a phase shift. The finding of the log oscillations in the Hall resistance supports the physical mechanism as a general quantum effect originating from the resonant scattering. Combined with theoretical simulations, we further clarify the origin of the log-periodic oscillations and the DSI in the topological materials. This work evidences the universality of the DSI in the Dirac materials and provides indispensable information for a full understanding of this novel phenomenon.
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http://dx.doi.org/10.1093/nsr/nwz110DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8291527PMC
October 2019

Sleep duration and risk of all-cause and disease-specific mortality in adult cancer survivors.

J Evid Based Med 2021 Oct 14. Epub 2021 Oct 14.

Department of Sociology & Institute for Empirical Social Science Research, School of Humanities and Social Sciences, Xi'an Jiaotong University, Xi'an, China.

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http://dx.doi.org/10.1111/jebm.12451DOI Listing
October 2021

New Tetramic Acid Derivatives From the Deep-Sea-Derived Fungus sp. SCSIO06868 With SARS-CoV-2 M Inhibitory Activity Evaluation.

Front Microbiol 2021 27;12:730807. Epub 2021 Sep 27.

CAS Key Laboratory of Tropical Marine Bio-Resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, South China Sea Institute of Oceanology, Chinese Academy of Sciences (CAS), Guangzhou, China.

Three new tetramic acid derivatives (-) and a new polyketide () along with eight known compounds (-) were isolated from cultures of the deep-sea-derived fungus sp. SCSIO06868. Four new structures were elucidated by analysis of one-dimensional/two-dimensional nuclear magnetic resonance (NMR) data and high-resolution electrospray ionization mass spectrometry. Their absolute configurations were established by X-ray crystallography analysis and comparison of the experimental and reported electronic circular dichroism (ECD) values or specific optical rotation. Compound exhibited potent, selective inhibitory activities against and methicillin-resistant with minimum inhibitory concentration values of both 2.5 μg/ml. Also, compound showed weak antiviral activity against severe acute respiratory syndrome coronavirus 2 main protease, which was responsible for the coronavirus disease 2019 pandemic.
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http://dx.doi.org/10.3389/fmicb.2021.730807DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8503681PMC
September 2021

Influence of regional emission controls on the chemical composition, sources, and size distributions of submicron aerosols: Insights from the 2014 Nanjing Youth Olympic Games.

Sci Total Environ 2021 Oct 7;807(Pt 2):150869. Epub 2021 Oct 7.

Department of Environmental Toxicology, University of California Davis, Davis, CA 95616, USA.

High-intensity emission controls were implemented in Nanjing and in 8 surrounding cities to ensure good air quality during the 2014 summer Youth Olympic Games (YOG). An Aerodyne soot-particle aerosol mass spectrometer (SP-AMS) was deployed at a downwind site of downtown Nanjing to investigate the chemical composition, sources, and size distribution of submicron aerosols (PM), in response to emission control policies. However, results show that emission controls played a negligible role in reducing PM concentration during the YOG period, yet primary precursors such as NO and SO were decreased by 10-20%. Low wind speed, high relative humidity, and high ozone (O) concentration likely play a significant role in the production and accumulation of the oxygenated organic aerosol (OOA) and the secondary inorganic aerosols (SIA) in summer Nanjing. We propose that long-term regional emission reduction could be a solution for future air pollution mitigation strategies in downwind cities of the YRD region, and that seasonal meteorological characteristics in a specific region should be considered before emission control policies are made.
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http://dx.doi.org/10.1016/j.scitotenv.2021.150869DOI Listing
October 2021

Estimation of Nuclear Medicine Exposure Measures Based on Intelligent Computer Processing.

J Healthc Eng 2021 27;2021:4102183. Epub 2021 Sep 27.

Hangzhou Dianzi University, Hangzhou,, Zhejiang 31000, China.

This paper provides an in-depth discussion and analysis of the estimation of nuclear medicine exposure measurements using computerized intelligent processing. The focus is on the study of energy extraction algorithms to obtain a high energy resolution with the lowest possible ADC sampling rate and thus reduce the amount of data. This paper focuses on the direct pulse peak extraction algorithm, polynomial curve fitting algorithm, double exponential function curve fitting algorithm, and pulse area calculation algorithm. The detector output waveforms are obtained with an oscilloscope, and the analysis module is designed in MATLAB. Based on these algorithms, the data obtained from six different lower sampling rates are analyzed and compared with the results of the high sampling rate direct pulse peak extraction algorithm and the pulse area calculation algorithm, respectively. The correctness of the compartment model was checked, and the results were found to be realistic and reliable, which can be used for the analysis of internal exposure data in radiation occupational health management, estimation of internal exposure dose for nuclear emergency groups, and estimation of accidental internal exposure dose. The results of the compartment model of the respiratory tract and the compartment model of the digestive tract can be used to calculate the distribution and retention patterns of radionuclides and their compounds in the body, which can be used to assess the damage of radionuclide internal contamination and guide the implementation of medical treatment.
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http://dx.doi.org/10.1155/2021/4102183DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8490043PMC
September 2021

Development and external validation of a prognostic model for survival of people living with HIV/AIDS initiating antiretroviral therapy.

Lancet Reg Health West Pac 2021 Nov 7;16:100269. Epub 2021 Sep 7.

School of Public Health (Shenzhen), Sun Yat-sen University, Shenzhen, China.

Most existing prognostic models for people living with HIV/AIDS (PLWHA) were derived from cohorts in high-income settings established a decade ago and may not be applicable for contemporary patients, especially for patients in developing settings. The aim of this study was to develop and externally validate a prognostic model for survival in PLWHA initiating ART based on a large population-based cohort in China. We obtained data for patients from the Chinese National Free Antiretroviral Treatment Program database. The derivation cohort consisted of PLWHA treated between February 2004 and December 2019 in a tertiary center in Guangzhou, South China, and validation cohort of patients treated between February 2004 to December 2018 in another tertiary hospital in Shenyang, Northeast China. We included ART-naive patients aged above 16 who initiated a combination ART regimen containing at least three drugs and had at least one follow-up record. We assessed 20 candidate predictors including patient characteristics, disease characteristics, and laboratory tests for an endpoint of death from all causes. The prognostic model was developed from a multivariable cox regression model with predictors selected using the least absolute shrinkage and selection operator (Lasso). To assess the model's predictive ability, we quantified the discriminative power using the concordance (C) statistic and calibration accuracy by comparing predicted survival probabilities with observed survival probabilities estimated with the Kaplan-Meier method. The derivation cohort included 16481 patients with a median follow-up of 3·41 years, among whom 735 died. The external validation cohort comprised 5751 participants with a median follow-up of 2·71 years, of whom 185 died. The final model included 10 predictors: age, body mass index, route of HIV acquisition, coinfection with tuberculosis, coinfection with hepatitis C virus, haemoglobin, CD4 cell count, platelet count, aspartate transaminase, and plasma glucose. The C-statistic was 0·84 (95% confidence interval 0·82-0·85) in internal validation after adjustment of optimism and 0·84 (0·82-0·87) in external validation, which remained consistently above 0·75 in all landmark time points within five years of follow up when using time-updated laboratory measurements. The calibration accuracy was satisfactory in both derivation and validation cohorts. We have developed and externally validated a model to predict long-term survival in PLWHA on ART. This model could be applied to individualized patient counseling and management during treatment, and future innovative trial design. Natural Science Foundation of China Excellent Young Scientists Fund, Natural Science Foundation of China International/Regional Research Collaboration Project, Natural Science Foundation of China Young Scientist Fund, the National Science and Technology Major Project of China,National Special Research Program of China for Important Infectious Diseases, 13th Five-Year Key Special Project of Ministry of Science and Technology, and the Joint-innovation Program in Healthcare for Special Scientific Research Projects of Guangzhou.
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http://dx.doi.org/10.1016/j.lanwpc.2021.100269DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8427312PMC
November 2021

High-Temperature Oxidation Behavior of AlTiNiCuCo High-Entropy Alloys.

Materials (Basel) 2021 Sep 15;14(18). Epub 2021 Sep 15.

Department of Material Science and Chemical Engineering, Harbin Engineering University, Harbin 150001, China.

In this study, the high-temperature oxidation behavior of a series of AlTiNiCuCo high-entropy alloys (HEAs) was explored. The AlTiNiCuCo (x = 0.5, 0.75, 1.0, 1.25, 1.5) series HEAs were prepared using a vacuum induction melting furnace, in which three kinds of AlTiNiCuCo (x = 0.5, 1.0, 1.5) alloys with different Co contents were oxidized at 800 °C for 100 h, and their oxidation kinetic curves were determined. The microstructure, morphology, structure, and phase composition of the oxide film surface and cross-sectional layers of AlTiNiCuCo series HEAs were analyzed using scanning electron microscopy (SEM), energy-dispersive spectrometry (EDS), and X-ray diffraction (XRD). The influence of Co content on the high-temperature oxidation resistance of the HEAs was discussed, and the oxidation mechanism was summarized. The results indicate that, at 800 °C, the AlTiNiCuCo (x = 0.5, 1.0, 1.5) series HEAs had dense oxide films and certain high-temperature oxidation resistance. With increasing Co content, the high-temperature oxidation resistance of the alloys also increased. With increasing time at high temperature, there was a significant increase in the contents of oxide species and Ti on the oxide film surface. In the process of high-temperature oxidation of AlTiNiCuCo series HEAs, the interfacial reaction, in which metal elements and oxygen in the alloy form ions through direct contact reaction, initially dominated, then the diffusion process gradually became the dominant oxidation factor as ions diffused and were transported in the oxide film.
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http://dx.doi.org/10.3390/ma14185319DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8468823PMC
September 2021

Decreased biofilm formation in Proteus mirabilis after short-term exposure to a simulated microgravity environment.

Braz J Microbiol 2021 Sep 23. Epub 2021 Sep 23.

Department of Respiratory and Critical Care Medicine, The Second Medical Center & National Clinical Research Center for Geriatric Disease, Medical School of Chinese PLA, Beijing, People's Republic of China.

Background: Microbes threaten human health in space exploration. Studies have shown that Proteus mirabilis has been found in human space habitats. In addition, the biological characteristics of P. mirabilis in space have been studied unconditionally. The simulated microgravity environment provides a platform for understanding the changes in the biological characteristics of P. mirabilis.

Objective: This study intends to explore the effect of simulated microgravity on P. mirabilis, the formation of P. mirabilis biofilm, and its related mechanism.

Methods: The strange deformable rods were cultured continuously for 14 days under microgravity simulated in high-aspect rotating vessels (HARVs). The morphology, growth rate, metabolism, and biofilm formation of the strain were measured, and the phenotypic changes of P. mirabilis were evaluated. Transcriptome sequencing was used to detect differentially expressed genes under simulated microgravity and compared with phenotype.

Results: The growth rate, metabolic ability, and biofilm forming ability of P. mirabilis were lower than those of normal gravity culture under the condition of simulated microgravity. Further analysis showed that the decrease of growth rate, metabolic ability, and biofilm forming ability may be caused by the downregulation of related genes (pstS, sodB, and fumC).

Conclusion: The simulated microgravity condition enables us to explore the potential relationship between bacterial phenotype and molecular biology, thus opening up a suitable and constructive method for medical fields that have not been explored before. It provides a certain strategy for the treatment of P. mirabilis infectious diseases in space environment by exploring the microgravity of P. mirabilis.
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http://dx.doi.org/10.1007/s42770-021-00588-yDOI Listing
September 2021

Effects of Simulated Microgravity on the Physiology of and Multiomic Analysis.

Front Microbiol 2021 27;12:701265. Epub 2021 Aug 27.

Department of Respiratory and Critical Care Medicine, The Second Medical Center and National Clinical Research Center for Geriatric Disease, Chinese PLA General Hospital, Beijing, China.

Many studies have shown that the space environment plays a pivotal role in changing the characteristics of conditional pathogens, especially their pathogenicity and virulence. However, , a type of conditional pathogen that has shown to a gradual increase in clinical morbidity in recent years, has rarely been reported for its impact in space. In this study, was exposed to a simulated microgravity (SMG) environment in high-aspect ratio rotating-wall vessel bioreactors for 14days, while the control group was exposed to the same bioreactors in a normal gravity (NG) environment. Then, combined phenotypic, genomic, transcriptomic, and proteomic analyses were conducted to compare the influence of the SMG and NG on . The results showed that in simulated microgravity displayed an increased growth rate, enhanced biofilm formation ability, increased swimming motility, and metabolic alterations compared with those of in normal gravity and the original strain of . Clusters of Orthologous Groups (COG) annotation analysis indicated that the increased growth rate might be related to the upregulation of differentially expressed genes (DEGs) involved in energy metabolism and conversion, secondary metabolite biosynthesis, transport and catabolism, intracellular trafficking, secretion, and vesicular transport. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses showed that the increased motility might be associated the upregulation of differentially expressed proteins (DEPs) involved in locomotion, localization, biological adhesion, and binding, in accordance with the upregulated DEGs in cell motility according to COG classification, including pilP, pilM, flgE, flgG, and ronN. Additionally, the increased biofilm formation ability might be associated with the upregulation of DEPs involved in biofilm formation, the bacterial secretion system, biological adhesion, and cell adhesion, which were shown to be regulated by the differentially expressed genes (chpB, chpC, rpoN, pilA, pilG, pilH, and pilJ) through the integration of transcriptomic and proteomic analyses. These results suggested that simulated microgravity might increase the level of corresponding functional proteins by upregulating related genes to alter physiological characteristics and modulate growth rate, motility, biofilm formation, and metabolism. In conclusion, this study is the first general analysis of the phenotypic, genomic, transcriptomic, and proteomic changes in under simulated microgravity and provides some suggestions for future studies of space microbiology.
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http://dx.doi.org/10.3389/fmicb.2021.701265DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8429793PMC
August 2021

Cadmium sulfide modified zinc oxide heterojunction harvesting ultrasonic mechanical energy for efficient decomposition of dye wastewater.

J Colloid Interface Sci 2021 Sep 4;607(Pt 1):412-422. Epub 2021 Sep 4.

Department of Materials Science and Engineering, Zhejiang Normal University, Jinhua 321004, China; Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, Institute of Physical Chemistry, Zhejiang Normal University, Jinhua 321004, China. Electronic address:

CdS/ZnO nano heterojunction was synthesized and applied in piezocatalytic degradation of rhodamine B (RhB) under ultrasonic vibration. The optimal CdS/ZnO composite with a CdS content of 35% presented the highest RhB degradation efficiency (98.8%) in 90 min. The degradation rate reached 4.02 h, which was 5.6 and 2.8 times higher than that of CdS and ZnO, respectively. In addition, CdS/ZnO showed high stability in the piezocatalytic reaction. The as-prepared CdS/ZnO piezocatalysts were characterized by multiple techniques to reveal the nature behind the enhanced catalytic activity. Results indicated that CdS nanoparticles were tightly loaded onto the surface of ZnO. The piezoelectric properties of the CdS/ZnO composites were the origin of their piezocatalytic behavior. The suitable band potentials of CdS and ZnO triggered the formation of a heterojunction structure, thereby driving the second distribution of the piezo-induced charge carriers. Therefore, the separation efficiency of charge carriers and the piezocatalytic performance was greatly elevated. The high piezocatalytic activity and stability indicated that CdS/ZnO may have wide application potential in the piezocatalytic degradation of organic dyes by using ultrasonic vibration energy.
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http://dx.doi.org/10.1016/j.jcis.2021.09.004DOI Listing
September 2021

Gold-catalyzed oxidation of terminal alkynes to glyoxals and their reactions with 2-phenylimidazo[1,2-]pyridines: one-pot synthesis of 1,2-diones.

Org Biomol Chem 2021 Oct 20;19(40):8735-8739. Epub 2021 Oct 20.

CAS Key Laboratory of Tropical Marine Bio-Resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, Research Center for Marine Microbes, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China.

A novel one-pot protocol for the convenient and efficient synthesis of (2-phenylimidazo[1,2-]pyridin-3-yl)alkane-1,2-diones (3) in good yields (32-88%) from 2-phenylimidazo[1,2-]pyridines (1) and terminal alkynes (2) has been established with a wide range of substrate scope. A tandem reaction sequence containing gold-catalyzed double oxidations of terminal alkynes to generate glyoxals, nucleophilic addition of 2-phenylimidazo[1,2-]pyridines to glyoxals to yield α-hydroxyl ketones, and oxygenation of the α-hydroxyl ketones to afford the final products 3 under air atmosphere is involved in this method. Simple operation, mild reaction conditions, and widely available substrates make this strategy more affordable.
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http://dx.doi.org/10.1039/d1ob01507aDOI Listing
October 2021

Progress and challenges of network meta-analysis.

J Evid Based Med 2021 Sep 30;14(3):218-231. Epub 2021 Aug 30.

Public Health and Health Services Research, Norwich Medical School, University of East Anglia, Norwich, UK.

In the past years, network meta-analysis (NMA) has been widely used among clinicians, guideline makers, and health technology assessment agencies and has played an important role in clinical decision-making and guideline development. To inform further development of NMAs, we conducted a bibliometric analysis to assess the current status of published NMA methodological studies, summarized the methodological progress of seven types of NMAs, and discussed the current challenges of NMAs.
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http://dx.doi.org/10.1111/jebm.12443DOI Listing
September 2021

Serum Cystatin C Predicts Stroke Clinical Outcomes at 1 Year Independent of Renal Function.

Front Neurol 2021 11;12:676872. Epub 2021 Aug 11.

Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China.

Serum cystatin C (CysC) is a sensitive marker of renal function to predict cardiovascular diseases. We aimed to investigate the predictive value of CysC for clinical outcomes independent of renal function in patients with acute ischemic stroke (AIS). We measured serum CysC levels in 10,256 AIS patients from Third China National Stroke Registry (CNSR-III). The primary outcome was a combination of all-cause mortality and major disability (modified Rankin scale score, 3-6). Secondary outcomes included stroke recurrence and combined vascular events at 1 year. Outcomes were analyzed using logistic regression and Cox proportional hazards models, respectively. The median CysC of included patients was 0.95 mg/l (interquartile range, 0.83-1.10 mg/l). A U-shaped association was observed between CysC and primary outcome (all-cause mortality or major disability) [quartile (Q)1 vs. Q2: adjusted odds ratio (aOR) 1.29, 95% CI 1.06-1.58, = 0.012; Q3 vs. Q2: aOR 1.12, 95% CI 0.93-1.35, = 0.242; Q4 vs. Q2: aOR 1.35, 95% CI 1.10-1.65, = 0.004]. A similar trend also existed in "preserved renal function" patients. Adding CysC to a model containing conventional risk factors improved the model performance with integrated discrimination improvement (IDI) of 0.13% ( = 0.016) and net reclassification index (NRI) of 13.10% ( <0.001) for primary outcome. No significant association was observed for stroke recurrence or combined vascular event rate in different CysC quartiles. CysC showed a U-shaped correlation with 1-year stroke clinical outcome, suggesting that serum CysC may not only be a simple candidate marker of renal function.
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http://dx.doi.org/10.3389/fneur.2021.676872DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8385197PMC
August 2021

The Effects of Waste Cement on the Bioavailability, Mobility, and Leaching of Cadmium in Soil.

Int J Environ Res Public Health 2021 08 23;18(16). Epub 2021 Aug 23.

College of Ecology and Environment, Hainan University, Haikou 570228, China.

Waste cement is a construction and demolition waste produced from old buildings' demolition and transformation. In recent years, the recycling of recycled concrete is limited to the use of recycled aggregate, and the research on the utilization of waste cement in waste concrete is scarce. This study explored the effective application of waste cement for the adsorption of cadmium (Cd) from an aqueous solution and the bioavailability and immobility of Cd in soil. Results showed that the maximum adsorption capacities of ordinary Portland cement(OPC) paste, fly ash cement (FAC) paste, and zeolite cement (ZEC) paste for Cd were calculated to be 10.97, 9.47, 4.63 mg·g, respectively. The possible mechanisms for Cd adsorption in the solution by waste cement mainly involve precipitation by forming insoluble Cd compounds in alkaline conditions, and ion exchange for Cd with the exchangeable calcium ions in waste cement, which were confirmed by XRD and SEM. Results from diethylene triaminepentaacetic acid (DTPA) extraction and toxicity characteristic leaching procedure (TCLP) implied reduction of the Cd mobility. DTPA-extractable Cd decreased by 52, 48 and 46%, respectively, by adding 1% OPC, FAC and ZEC. TCLP-extractable Cd decreased by 89.0, 80.3, and 56.0% after 1% OPC, FAC, and ZEC treatment, respectively. BCR analyses indicate that OPC, FAC, and ZEC applications increased the percentage of Cd in residual fraction and induced a high reduction in the acid-soluble Cd proportion. The leaching column test further confirmed a reduction in Cd mobility by waste cement treated under continuous leaching of simulated acid rain (SAR). Therefore, waste cement exhibited a significant enhancement in the immobilization of Cd under simulated acid rain (SAR) leaching. In summary, the application of alkaline waste cement could substantially remove Cd from wastewater and reduce Cd mobility and bioavailability in contaminated soil.
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http://dx.doi.org/10.3390/ijerph18168885DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8393406PMC
August 2021

Initial Decomposition Mechanism of 3-Nitro-1,2,4-triazol-5-one (NTO) under Shock Loading: ReaxFF Parameterization and Molecular Dynamic Study.

Molecules 2021 Aug 9;26(16). Epub 2021 Aug 9.

School of Materials Science & Engineering, Beijing Institute of Technology, Zhongguancun South Street 5, Beijing 100081, China.

We report a reactive molecular dynamic (ReaxFF-MD) study using the newly parameterized ReaxFF-lg reactive force field to explore the initial decomposition mechanism of 3-Nitro-1,2,4-triazol-5-one (NTO) under shock loading (shock velocity >6 km/s). The new ReaxFF-lg parameters were trained from massive quantum mechanics data and experimental values, especially including the bond dissociation curves, valence angle bending curves, dihedral angle torsion curves, and unimolecular decomposition paths of 3-Nitro-1,2,4-triazol-5-one (NTO), 1,3,5-Trinitro-1,3,5-triazine (RDX), and 1,1-Diamino-2,2-dinitroethylene (FOX-7). The simulation results were obtained by analyzing the ReaxFF dynamic trajectories, which predicted the most frequent chain reactions that occurred before NTO decomposition was the unimolecular NTO merged into clusters ((CHON)). Then, the NTO dissociated from (CHON) and started to decompose. In addition, the paths of NO elimination and skeleton heterocycle cleavage were considered as the dominant initial decomposition mechanisms of NTO. A small amount of NTO dissociation was triggered by the intermolecular hydrogen transfer, instead of the intramolecular one. For α-NTO, the calculated equation of state was in excellent agreement with the experimental data. Moreover, the discontinuity slope of the shock-particle velocity equation was presented at a shock velocity of 4 km/s. However, the slope of the shock-particle velocity equation for β-NTO showed no discontinuity in the shock wave velocity range of 3-11 km/s. These studies showed that MD by using a suitable ReaxFF-lg parameter set, could provided detailed atomistic information to explain the shock-induced complex reaction mechanisms of energetic materials. With the ReaxFF-MD coupling MSST method and a cheap computational cost, one could also obtain the deformation behaviors and equation of states for energetic materials under conditions of extreme pressure.
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http://dx.doi.org/10.3390/molecules26164808DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8400475PMC
August 2021

Humidity Dependence of the Condensational Growth of α-Pinene Secondary Organic Aerosol Particles.

Environ Sci Technol 2021 Aug 18. Epub 2021 Aug 18.

School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States.

The influence of relative humidity (RH) on the condensational growth of organic aerosol particles remains incompletely understood. Herein, the RH dependence was investigated via a series of experiments for α-pinene ozonolysis in a continuously mixed flow chamber in which recurring cycles of particle growth occurred every 7 to 8 h at a given RH. In 5 h, the mean increase in the particle mode diameter was 15 nm at 0% RH and 110 nm at 75% RH. The corresponding particle growth coefficients, representing a combination of the thermodynamic driving force and the kinetic resistance to mass transfer, increased from 0.35 to 2.3 nm s. The chemical composition, characterized by O:C and H:C atomic ratios of 0.52 and 1.48, respectively, and determined by mass spectrometry, did not depend on RH. The (MOSAIC) was applied to reproduce the observed size- and RH-dependent particle growth by optimizing the diffusivities within the particles of the condensing molecules. The values increased from 5 α × 10 at 0% RH to 2 α × 10 cm s at 75% RH for mass accommodation coefficients α of 0.1 to 1.0, highlighting the importance of particle-phase properties in modeling the growth of atmospheric aerosol particles.
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http://dx.doi.org/10.1021/acs.est.1c01738DOI Listing
August 2021

Tumor-associated macrophage-derived transforming growth factor-β promotes colorectal cancer progression through HIF1-TRIB3 signaling.

Cancer Sci 2021 Oct 23;112(10):4198-4207. Epub 2021 Aug 23.

Department of Interventional Treatment, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin's Clinical Research Center for Cancer, Tianjin Medical University Cancer Institute and Hospital, Tianjin, China.

Tumor-associated macrophages (TAMs), one of the most common cell components in the tumor microenvironment, have been reported as key contributors to cancer-related inflammation and enhanced metastatic progression of tumors. To explore the underlying mechanism of TAM-induced tumor progression, TAMs were isolated from colorectal cancer patients, and the functional interaction with colorectal cancer cells was analyzed. Our study found that coculture of TAMs contributed to a glycolytic state in colorectal cancer, which promoted the stem-like phenotypes and invasion of tumor cells. TAMs produced the cytokine transforming growth factor-β to support hypoxia-inducible factor 1α (HIF1α) expression, thereby upregulating Tribbles pseudokinase 3 (TRIB3) in tumor cells. Elevated expression of TRIB3 resulted in activation of the β-catenin/Wnt signaling pathway, which eventually enhanced the stem-like phenotypes and cell invasion in colorectal cancer. Our findings provided evidence that TAMs promoted colorectal cancer progression in a HIF1α/TRIB3-dependent manner, and blockade of HIF1α signals efficiently improved the outcome of chemotherapy, describing an innovative approach for colorectal cancer treatment.
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http://dx.doi.org/10.1111/cas.15101DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8486199PMC
October 2021

The complete chloroplast genome of Siebold & Zuccarini (Rhamnaceae).

Mitochondrial DNA B Resour 2021 26;6(9):2489-2490. Epub 2021 Jul 26.

Key Laboratory of Biodiversity Conservation in Southwest China, State Forestry Administration, Southwest Forestry University, Kunming, China.

Siebold & Zuccarini is deciduous shrub or small tree plant that widely distributed in temperate and tropical regions of East to Southeast Asia. It has a chloroplast genome structure similar to that of other species of . It is 160,454 bp in size, including a large single-copy (LSC) region of 88,884 bp, a small single-copy (SSC) region of 18,734 bp and a pair of inverted repeats (IRs) of 26,418 bp. A total of 122 genes were annotated, including 80 protein-coding genes, 38 transfer RNA (tRNA) genes, and 4 rRNA genes. The overall GC content is 30.71%. Phylogenetic analysis shows that is clustered with and
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http://dx.doi.org/10.1080/23802359.2021.1945502DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8317963PMC
July 2021

ONECUT2 which is targeted by hsa-miR-15a-5p enhances stemness maintenance of gastric cancer stem cells.

Exp Biol Med (Maywood) 2021 Aug 9:15353702211038496. Epub 2021 Aug 9.

Department of General Surgery, The First Affiliated Hospital of Soochow University, Suzhou 215006, PR China.

Gastric cancer is the third dominating cause of cancer-associated death. MiroRNAs are potential clinical tools for cancer diagnosis and therapy. In this project, we demonstrated significant overexpression of ONECUT2 and down-regulation of hsa-miR-15a-5p in gastric cancer via bioinformatics analysis and assays. Meanwhile, ONECUT2 expression is related to clinical prognosis in gastric cancer and inversely proportional to the differentiation degree of gastric adenocarcinoma according to immunohistochemistry results. Then, we separated CD133+/CD44+ MKN45 by flow cytometry and found that, compared with parental MKN45, CD133+/CD44+ MKN45 gastric cancer stem cells (GCSCs) had higher levels of ONECUT2 and lower levels of hsa-miR-15a-5p. In addition, we applied both and assays to demonstrate hsa-miR-15a-5p regulates the stemness maintenance, epithelial-mesenchymal transition, and chemosensitivity of GCSCs through targeting ONECUT2. Also, hsa-miR-15a-5p inhibits G0 phase block of GCSCs by regulating ONECUT2/β-catenin signaling pathway. However, this study has provided novel perspective into the dynamic control of cancer stem cells for advanced gastric cancer treatment.
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http://dx.doi.org/10.1177/15353702211038496DOI Listing
August 2021

Magnetic-field-induced robust zero Hall plateau state in MnBiTe Chern insulator.

Nat Commun 2021 Jul 30;12(1):4647. Epub 2021 Jul 30.

State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing, China.

The intrinsic antiferromagnetic topological insulator MnBiTe provides an ideal platform for exploring exotic topological quantum phenomena. Recently, the Chern insulator and axion insulator phases have been realized in few-layer MnBiTe devices at low magnetic field regime. However, the fate of MnBiTe in high magnetic field has never been explored in experiment. In this work, we report transport studies of exfoliated MnBiTe flakes in pulsed magnetic fields up to 61.5 T. In the high-field limit, the Chern insulator phase with Chern number C = -1 evolves into a robust zero Hall resistance plateau state. Nonlocal transport measurements and theoretical calculations demonstrate that the charge transport in the zero Hall plateau state is conducted by two counter-propagating edge states that arise from the combined effects of Landau levels and large Zeeman effect in strong magnetic fields. Our result demonstrates the intricate interplay among intrinsic magnetic order, external magnetic field, and nontrivial band topology in MnBiTe.
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http://dx.doi.org/10.1038/s41467-021-25002-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8324822PMC
July 2021

Low diffusive nitrogen loss of urban inland waters with high nitrogen loading.

Sci Total Environ 2021 May 26;789:148023. Epub 2021 May 26.

Key Laboratory of Water and Sediment Sciences of Ministry of Education, State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China.

Little is known about the exchange of gaseous nitrogen (N) with the atmosphere from urban inland waters, which are characterized by low carbon-to‑nitrogen ratios and low nitrogen-to‑phosphorus ratios. Here, we studied diffusive nitrogen loss based on the measurement of dissolved N concentrations and related gene abundance of N production and fixation in rivers and lakes in the megacity of Beijing, China, between 2018 and 2020. The excess dissolved N (△N) ranged from -51.2 to 56.8 μmol L (average - 0.03 ± 13.8 μmol L), and approximately 43% of the river samples and 72% of the lake samples being undersaturated with N, suggesting that the lakes mainly acted as a role of N sink. The N removal fraction (△N/DIN, average 3.5 ± 4.3%) at the sites of rivers with positive △N was lower than that in other rivers around the world. The average N flux (0.8 ± 23.9 mmol m d) in the urban rivers was also lower than that in other rivers. The low carbon-to‑nitrogen ratios in Beijing inland waters are not beneficial for N production during denitrification, and low nitrogen-to‑phosphorus ratios potentially favor N fixation with a high abundance of the nitrogenase nifH gene in the sediment, resulting in low net N production. The traditional paradigm is that rivers constantly lose vast N to the atmosphere via denitrification and anammox, but this study indicates that urban inland rivers emit negligible N even under high nitrogen loading.
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http://dx.doi.org/10.1016/j.scitotenv.2021.148023DOI Listing
May 2021

PLA2G4A promotes right-sided colorectal cancer progression by inducing CD39+γδ Treg polarization.

JCI Insight 2021 Aug 23;6(16). Epub 2021 Aug 23.

Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Tianjin's Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin, China.

The γδ T cell is a promising candidate cell in tumor immunotherapy. However, γδ T cells polarize to CD39+γδ Tregs upon colorectal cancer (CRC) induction, and the underlying mechanism remains unclear. Here, we show that the frequency of CD39+γδ Tregs, which positively correlated with poor prognosis, was significantly higher in right-sided CRC (RSCRC) than in the left-sided CRC (LSCRC). Interestingly, CD39+γδ Tregs from RSCRC showed stronger immunosuppressive phenotype and function than LSCRC. Furthermore, the quantitative mass spectrometry data show that CD39+γδ Treg polarization was related to the abnormal activation of the Phospholipase a2-IVa/Arachidonic acid (PLA2G4A/AA) metabolic pathway in RSCRC. Using an in vitro coculture system and an orthotopic murine model of CRC, we show that the overexpression of Pla2g4a in CT26 cells induced CD39+γδ Tregs, inhibiting the antitumor immune response. Finally, we found that the overall survival of the PLA2G4Ahi group was significantly shortened compared with PLA2G4Alo RSCRC, while the survival of LSCRC showed the opposite. Collectively, RSCRC with abnormal PLA2G4A expression educates γδ T cells into CD39+γδ Tregs to promote tumor progression and metastasis. Our work highlights the interaction between cancer cells and immune cells by distinguishing the primary tumor site and deepens the understanding of the tumor microenvironment and immunosuppression.
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http://dx.doi.org/10.1172/jci.insight.148028DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8409991PMC
August 2021

Expression of miR-214 in pancreatic cancer and its effect on the biological function of pancreatic cancer cells.

J BUON 2021 May-Jun;26(3):1111-1120

Medical School, Kumming University of Science and Technology, Kumming, China. 2Department of Hepatobiliary and Pancreatic Surgery, First People's Hospital of Yunnan Province, affiliated Hospital of KMUST, Kumming, Yunnan, China.

Purpose: To study the expression and biological function of microRNA 214 (miR-214) in pancreatic cancer.

Methods: 101 patients with pancreatic cancer who came from First People's Hospital of Yunnan Province from December 2013 to December 2016 were selected. 101 pancreatic cancer tissues and 101 adjacent tissues were resected and collected. The miR-214 expression was detected by qRT-PCR. Then the pancreatic cancer cell line AsPC-1 and SW1990 were transfected. MTT assay was used to detect cell viability and flow cytometry was used to detect apoptosis. Transwell chamber assay was used to detect the invasion and migration of cells in vitro. The protein expressions of ING4 in AsPC-1 and SW1990 cells were detected by Western blot.

Results: The relative expression of miR-214 in pancreatic cancer was significantly higher than that in adjacent tissues (p<0.05). There was a statistically significant difference between the expression level of miR-214 and T stage of pancreatic cancer (p<0.05). The relative expression of ING4 protein in SW1990 cells of miR-214 mimics group was significantly lower than that of miR-214 control mimics group (p<0.05), and that in AsPC-1 cells of the miR-214 inhibitors group was significantly higher than that in the miR-214 control inhibitors group (p<0.05).

Conclusion: In conclusion, the expression of miR-214 is highly expressed in pancreatic cancer tissues, and the down-regulation of ING4 protein expression can inhibit the proliferation, invasion and migration of pancreatic cancer cells, promote their apoptosis, and can be used as a new molecular target for the diagnosis and treatment of pancreatic cancer.
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July 2021

Dissolved organic carbon drives nutrient cycling via microbial community in paddy soil.

Chemosphere 2021 Dec 10;285:131472. Epub 2021 Jul 10.

Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 10085, China.

Microbial mediated iron cycling drives the biogeochemical cycling of carbon, nitrogen, sulfur, and phosphorus. However, the fate of the microbial community and the relative metabolic pathways in paddy soil after the addition of biogas slurry are poorly understood. In this study, the response of functional genes was investigated by growing one-season rice in paddy soils in a pot experiment. Seven treatments were prepared: 1) control (CK); 2) organic carbon (OC); 3) fertilizer (F); 4) 5% of biogas slurry (B05); 5) 10% of biogas slurry (B10); 6) 15% of biogas slurry (B15); 7) 20% of biogas slurry (B20). In the biogas slurry treatments, Geobacter increased more than in the other treatments during rice growth, which were structured by TOC. Particularly, in the B10 treatment, the relative abundance of Geobacter was 1.6 and 14.8 times higher than that of CK at the heading and mature stages, respectively. At the heading stage, the addition of biogas slurry and OC shifted the microbial phosphorus-transformation communities differently. There were no significant differences in the carbon, nitrogen, and sulfur metabolic pathways between the two treatments. At the mature stage, the carbon: nitrogen: phosphorus balance was significantly influenced by the regulation of functional gene expression and metabolic activities. These findings provide insight into the key factors affecting carbon, nitrogen, sulfur, phosphorus, and iron during rice growth after carbon inputs.
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http://dx.doi.org/10.1016/j.chemosphere.2021.131472DOI Listing
December 2021

Responses of soil N O emissions and their abiotic and biotic drivers to altered rainfall regimes and co-occurring wet N deposition in a semi-arid grassland.

Glob Chang Biol 2021 10 17;27(19):4894-4908. Epub 2021 Jul 17.

Microbial Ecology Centre LEM, INRAE UMR 1418, CNRS UMR 5557, VetAgroSup, Université de Lyon, Villeurbanne, France.

Global change factors such as changed rainfall regimes and nitrogen (N) deposition contribute to increases in the emission of the greenhouse gas nitrous oxide (N O) from the soil. In previous research, N deposition has often been simulated by using a single or a series of N addition events over the course of a year, but wet N deposition actually co-occurs with rainfall. How soil N O emissions respond to altered rainfall amount and frequency, wet N deposition, and their interactions is still not fully understood. We designed a three-factor, fully factorial experiment with factors of rainfall amounts (ambient, -30%) rainfall frequency (ambient, ±50%) and wet N deposition (with/without) co-occurring with rainfall in semi-arid grassland mesocosms, and measured N O emissions and their possible biotic and abiotic drivers. Across all treatments, reduced rainfall amount and N deposition increased soil N O emissions by 35% and 28%, respectively. A significant interactive effect was observed between rainfall amount and N deposition, and to a lesser extent between rainfall frequency and N deposition. Without N deposition, reduced rainfall amount and altered rainfall frequency indirectly affected soil N O emissions by changing the abundance of nirK and soil net N mineralization, and the changes in nirK abundance were indirectly driven by soil N availability rather than directly by soil moisture. With N deposition, both the abundance of nirK and the level of soil water-filled pore space contributed to changes in N O emissions in response to altered rainfall regimes, and the changes in the abundance of nirK were indirectly driven by plant N uptake and nitrifier (ammonia-oxidizing bacteria) abundance. Our results imply that unlike wetter grassland ecosystems, reduced precipitation may increase N O emissions, and N deposition may only slightly increase N O emissions in arid and semi-arid N-limited ecosystems that are dominated by grasses with high soil N uptake capacity.
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http://dx.doi.org/10.1111/gcb.15792DOI Listing
October 2021

Comparison Between Laparoscopic Sleeve Gastrectomy and Laparoscopic Greater Curvature Plication Treatments for Obesity: an Updated Systematic Review and Meta-Analysis.

Obes Surg 2021 09 5;31(9):4142-4158. Epub 2021 Jul 5.

Department of Gastrointestinal Surgery, The First Affiliated Hospital of Wannan Medical College, 2 Zheshan West Road, Wuhu, Anhui Province, China.

Bariatric surgery has been widely performed to treat morbid obesity. Our meta-analysis aims to provide an updated comparison between laparoscopic sleeve gastrectomy (LSG) and laparoscopic greater curvature plication (LGCP). Medline, EMBASE, Scopus, and Cochrane Central were searched. Ongoing clinical trials were identified from the clinicaltrials.gov website. References of the chosen literatures were manually reviewed for additional relevant studies. As a result, a total of 18 studies involving 1329 patients were selected. We demonstrated a significant higher excess weight loss (%EWL) after LSG at the 1-, 3-, 6-, 12-, and 18-month follow-up time points. However, no significant difference was found at 36 months. Body Mass Index Loss (BMIL) was better after LSG than LGCP at 12 and 24 months. The difference in the improvement of comorbidities (i.e., T2-DM, hypertension, and sleep apnea) did not reach statistical significance. The complications (i.e., bleeding, stenosis, leak, and abdominal pain), operative time, and length of hospital stay were comparable. More patients undergoing LGCP experienced nausea and vomiting. We obtained some different and new results compared to the previously published meta-analysis. Our meta-analysis showed significantly higher %EWL at 24 months (Z=2.08, p=0.04), significantly higher BMIL at 36 months (Z=9.11, p <0.00001), and significantly higher costs (Z=2.87, p=0.004) in the LSG group. In addition, for the first time, complications (i.e., GERD, wound infection, port-site hernia, and mortality) and improvement of dyslipidemia were compared between the two techniques. According to our pooled data, no significant differences were found in any of the above aspects. In conclusion, LSG is superior to LGCP with regard to providing effective weight loss in the short- and mid-term. LSG has a lower rate of minor complications, but was less effective when considering cost. The two procedures are similar in terms of improvement of comorbidities, major complications, operative time, and length of stay.
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http://dx.doi.org/10.1007/s11695-021-05538-zDOI Listing
September 2021

Cyclopentenone-Containing Tetrahydroquinoline and Geldanamycin Alkaloids from as Potential Anti-Androgens against Prostate Cancer Cells.

J Nat Prod 2021 07 6;84(7):2004-2011. Epub 2021 Jul 6.

CAS Key Laboratory of Tropical Marine Bio-resources and Ecology/Guangdong Key Laboratory of Marine Materia Medica/Innovation Academy of South China Sea Ecology and Environmental Engineering, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China.

Malaymycin (), a new cyclopentenone-containing tetrahydroquinoline alkaloid, and mccrearamycin E (), a geldanamycin analogue bearing a rare ring-contracted cyclopentenone moiety, and a -symmetric macrodiolide () were isolated from SCSIO41397. Their structures including absolute configurations were determined by detailed analyses of NMR and HRMS data and ECD calculations. The occurrence of mccrearamycin E () bearing a ring-contracted cyclopentenone is rare in the geldanamycin class. All isolated compounds were evaluated for their cytotoxicities against five cancer cell lines. As a result, compounds , , , and showed cytotoxicity against some or all of the five cancer cell lines with IC values ranging from 0.067 to 7.2 μM. In particular, compound inhibited the growth of C42B and H446 cell lines with IC values of 67 and 70 nM, respectively. Malaymycin () significantly induced cell cycle arrest at the G0/G1 phase in C42B cell lines and caused cell shrinkage and inhibited the expression of the androgen receptor (AR) at both the mRNA and protein levels in a dose-dependent manner. Further examination by qRT-PCR analysis showed that strongly suppressed the expression of AR target genes and in the C42B and 22RV1 cell lines, which suggested that might be a promising potential lead compound for the development of a treatment for the castration-resistant prostate cancer (CRPC).
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http://dx.doi.org/10.1021/acs.jnatprod.1c00297DOI Listing
July 2021

Effect of Pyrolysis Temperature on the Characterisation of Dissolved Organic Matter from Pyroligneous Acid.

Molecules 2021 Jun 4;26(11). Epub 2021 Jun 4.

Hainan Guowei Eco-Environment Co., Ltd., Haikou 570203, China.

Dissolved organic matter (DOM) greatly influences the transformation of nutrients and pollutants in the environment. To investigate the effects of pyrolysis temperatures on the composition and evolution of pyroligneous acid (PA)-derived DOM, DOM solutions extracted from a series of PA derived from eucalyptus at five pyrolysis temperature ranges (240-420 °C) were analysed with Fourier transform infrared spectroscopy, gas chromatography-mass spectroscopy, and fluorescence spectroscopy. Results showed that the dissolved organic carbon content sharply increased ( < 0.05) with an increase in pyrolysis temperature. Analysis of the dissolved organic matter composition showed that humic-acid-like substances (71.34-100%) dominated and other fluorescent components (i.e., fulvic-acid-like, soluble microbial by-products, and proteinlike substances) disappeared at high temperatures (>370 °C). The results of two-dimensional correlation spectroscopic analysis suggested that with increasing pyrolysis temperatures, the humic-acid-like substances became more sensitive than other fluorescent components. This study provides valuable information on the characteristic evolution of PA-derived DOM.
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http://dx.doi.org/10.3390/molecules26113416DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8200247PMC
June 2021

CuS/KTaNbO nanocomposite utilizing solar and mechanical energy for catalytic N fixation.

J Colloid Interface Sci 2021 Dec 22;603:220-232. Epub 2021 Jun 22.

Department of Materials Science and Engineering, Zhejiang Normal University, Jinhua 321004, China; Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, Institute of Physical Chemistry, Zhejiang Normal University, Jinhua 321004, China. Electronic address:

This work synthesized a novel CuS/KTaNbO (KTN) heterojunction composite and firstly applied it in photocatalytic and piezocatalytic reduction of N to NH. XRD, Raman, XPS, SEM, and TEM analyses indicate that CuS nanoparticles closely adhered to the surface of KTN nanorods, which facilitates the migration of electrons between the two semiconductors. Mott-Schottky and valence band XPS analysis shows that KNbO shows a higher conduction band than CuS, indicating that CuS mainly acts as electron trappers to capture the photogenerated electrons from KTN. Because of the great enhanced spatial separation of photogenerated charge carriers, the CuS/KTN presents much higher performance than pure KNT, which is further confirmed by H NMR analysis of the reaction solution. An interesting finding is that synthesized CuS/KTN not only performs well under light irradiation but also can work in an ultrasonic bath, indicating its great potential in photo/piezocatalytic conversion of N to NH. The optimal 10 %CuS/KTN shows an NH production rate of 36.2 μmol L g h under ultrasonic vibration, which reaches 7.4 times that of KTN. The electrons generated by KTN through the piezoelectric effect can be captured by CuS, which endows the electrons a longer life to participate in the reaction, thereby improving the catalytic reaction performance.
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http://dx.doi.org/10.1016/j.jcis.2021.06.107DOI Listing
December 2021

Pollution characteristics, sources and health risk of metals in urban dust from different functional areas in Nanjing, China.

Environ Res 2021 10 29;201:111607. Epub 2021 Jun 29.

Wuxi Center for Disease Control and Prevention (The Affiliated Wuxi Center for Disease Control and Prevention of Nanjing Medical University), No. 499 Jincheng Road, Wuxi, 214000, China. Electronic address:

Urban dust is an important medium of potential toxic metal (PTM) pollution that affects human health and the urban ecosystems. A total of 374 fugitive dust samples were collected in Nanjing, a fast-developing city in southern China, including six sub-types of dust (residential district, commercial district, industrial district, traffic district, cultural and educational district, green land). Chemical analysis of eighteen metal elements by inductively coupled plasma mass spectrometry was carried out to establish the sub-type sources profiles of fine particles for fugitive dust. The results show that these metals (Cu, Zn, Se, Sr, Mo, Cd, Sb, and Pb) are mainly from anthropogenic sources and present a high degree of pollution; Mn, As, and Ba are moderately affected by human activities and present a significant degree of pollution; Ni, Co, Cr, Tl, V, Be, and Ti mainly originate from natural sources and present significant, moderate and minimal degrees of pollution. For the dust types from different functional areas, the differences of enrichment factor (EF) values were relatively small. Metals were highly concentrated in dust from residential, cultural and educational district, which had high density population and would pose higher health risk. In all types of dust, the metals rich in crust (Ti, Mn, Ba, Sr) and the metals (Cu, Zn, Pb) closely connected with city activities were the main components. Factor analysis revealed that there were six main sources of metals in dust collected from Nanjing: industrial activity, building decoration, soil dust, metal smelting, traffic emissions, and brake abrasion. Generally, noncarcinogenic and carcinogenic health risks of metals found in dust are rarely found for children and adults based on health risk assessments. However, the noncarcinogenic risk of Pb in commercial districts for children should be noted because its hazard quotient was higher than the safety threshold level. For the accumulative health risk of eighteen metals, the noncarcinogenic risk values of dust from six functional areas for children were all over the threshold (1.0), whereas below 1.0 for adults. The difference between children and adults was relatively obvious. All accumulative risk values of carcinogenic metals did not exceed the carcinogenic risk threshold of 1 × 10, which suggested that no risk prevention measures were needed.
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http://dx.doi.org/10.1016/j.envres.2021.111607DOI Listing
October 2021
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