Publications by authors named "Xiaoke Wang"

188 Publications

Delayed neurological improvement is predictive to long-term clinical outcome on endovascular thrombectomy patients.

Interv Neuroradiol 2021 Sep 13:15910199211038207. Epub 2021 Sep 13.

Department of Neurology, 12579Medical School of Southeast University, Jinling Hospital, China.

Objectives: This study aims at exploring the 3-month outcome predicting ability of delayed neurological improvement and the cause of delayed neurological improvement.

Materials And Methods: Early neurological improvement and delayed neurological improvement were calculated to represent the neurological improvements. Good functional outcome was defined as a 90-day modified Rankin Scale score 0-2. We used multivariant logistic regression to explore the influential factors of good functional outcome as well as delayed neurological improvement. We applied net reclassification improvement and integrated discrimination improvement to assess the quantitative improvement of the predictive model.

Results: Early neurological improvement was observed in 50 (23%) patients and delayed neurological improvement exhibited in 67 (30%) patients. Early neurological improvement and delayed neurological improvement were both independent predictive factors to good functional outcome. In the basic model (adjusted for age, admission glucose level, baseline National Institute of Health Stroke Scale, and complications and number of retrieval attempts), early neurological improvement and delayed neurological improvement statistically improved the predictive ability (early neurological improvement: net reclassification improvement = 0.34, 95% confidence interval, 95% confidential interval (0.06, 0.69); integrated discrimination improvement = 0.05,  < 0.001; delayed neurological improvement: net reclassification improvement = 0.79, 95% confidential interval (0.47, 1.12); integrated discrimination improvement = 0.14,  < 0.001) delayed neurological improvement could predict clinical outcomes more accurately than early neurological improvement (early neurological improvement vs. delayed neurological improvement: integrated discrimination improvement = 0.09,  < 0.001). Moreover, delayed neurological improvement was affected by hypertension (odds ratio  = 0.40, 95% CI (0.18, 0.88),  = 0.02), early neurological improvement (odds ratio  = 20.10, 95% confidential interval (8.24, 19.02),  < 0.001), number of retrieval attempts (odds ratio  = 0.39, 95% confidential interval (0.24, 0.66),  < 0.001), and complication (odds ratio  = 0.25, 95% confidential interval (0.12, 0.54),  < 0.001).

Conclusions: Delayed neurological improvement could predict clinical outcomes more accurately than early neurological improvement. Hypertension, early neurological improvement, numbers of retrieval attempts, and complications were all predicting factors to delayed neurological improvement.
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http://dx.doi.org/10.1177/15910199211038207DOI Listing
September 2021

Leaf Morphological and Nutrient Traits of Common Woody Plants Change Along the Urban-Rural Gradient in Beijing, China.

Front Plant Sci 2021 26;12:682274. Epub 2021 Aug 26.

State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, China.

An increasing number of studies have found differences in the diversity of plant functional traits between urban and rural sites as a result of urbanization. However, the results remain inconsistent. In this study, we measured morphological and nutrient traits of 11 common woody plants along a continuous urban-rural gradient in Beijing, China. Leaf size (e.g., length, width, and area), specific leaf area, and leaf nitrogen and potassium contents decreased gradually and significantly along the urban-rural gradient, indicating that urbanization can enhance the capacity of plants to acquire resources for growth and production. Furthermore, soil nutrients and air temperature decreased along the urban-rural gradient, while air relative humidity increased. A structural equation model showed that these alterations in physical factors attributable to urbanization contributed directly or indirectly to changes in leaf functional traits, implying that changes in soil nutrients and micro-climate induced by urbanization may affect plant growth and production because of the improvement in resource acquisition capacity.
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http://dx.doi.org/10.3389/fpls.2021.682274DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8427184PMC
August 2021

Exposure of Mice during Spermatogenesis: A Role of Inhibitor Kinase 2 in Pro-Opiomelanocortin Neurons.

Environ Health Perspect 2021 Sep 8;129(9):97006. Epub 2021 Sep 8.

Department of Medicine Cardiology Division, University of Maryland School of Medicine, Baltimore, Maryland, USA.

Background: Epidemiological studies have shown that exposure to ambient fine particulate matter with aerodynamic diameter less than or equal to 2.5 μm () correlates with a decrease in sperm count, but the biological mechanism remains elusive.

Objectives: This study tested whether hypothalamic inflammation, an emerging pathophysiological mediator, mediates the development of lower epididymal sperm count due to exposure.

Methods: Inhibitor kinase 2 (IKK2) was conditionally knocked out either in all neurons or subtypes of hypothalamic neurons of mice. Effects of concentrated ambient (CAP) exposure on hypothalamic inflammation, the hypothalamic-pituitary-gonadal (HPG) axis, and epididymal sperm count of these mouse models were then assessed. Furthermore, to test whether hypothalamic inflammation is sufficient to decrease sperm production, we overexpressed constitutively active IKK2 (IKK2ca) either in all neurons or subtypes of hypothalamic neurons and assessed hypothalamic inflammation, the HPG axis, and sperm production of these overexpression mouse models.

Results: CAP-exposed wild-type control mice vs. filtered air (FA)-exposed wild-type control mice had a higher expression of hypothalamic inflammatory markers, lower functional indexes of the HPG axis, and a lower epididymal sperm count. In contrast, all these measurements for CAP- vs. FA-exposed mice deficient of IKK2 in all neurons were comparable. We also found that overexpression of IKK2ca in either all neurons or pro-opiomelanocortin (POMC) neurons only, but not in Agouti-related protein (AgRP) neurons only, resulted in lower functional indexes of the HPG axis and a lower epididymal sperm count. Moreover, we showed that CAP- vs. FA-exposed mice deficient of IKK2 in POMC neurons had a comparable expression of hypothalamic inflammatory markers, comparable functional indexes of the HPG axis, and a comparable epididymal sperm count.

Discussion: This mouse model study shows a causal role of IKK2 of POMC neurons in the development of lower epididymal sperm count due to exposure, providing a mechanistic insight into this emerging pathogenesis. https://doi.org/10.1289/EHP8868.
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http://dx.doi.org/10.1289/EHP8868DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8425520PMC
September 2021

Sequence specific integration by the family 1 casposase from Candidatus Nitrosopumilus koreensis AR1.

Nucleic Acids Res 2021 Aug 24. Epub 2021 Aug 24.

State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing210009, China.

Casposase, a homolog of Cas1 integrase, is encoded by a superfamily of mobile genetic elements known as casposons. While family 2 casposase has been well documented in both function and structure, little is known about the other three casposase families. Here, we studied the family 1 casposase lacking the helix-turn-helix (HTH) domain from Candidatus Nitrosopumilus koreensis AR1 (Ca. N. koreensis). The determinants for integration by Ca. N. koreensis casposase were extensively investigated, and it was found that a 13-bp target site duplication (TSD) sequence, a minimal 3-bp leader and three different nucleotides of the TSD sequences are indispensable for target specific integration. Significantly, the casposase can site-specifically integrate a broad range of terminal inverted repeat (TIR)-derived oligonucleotides ranging from 7-nt to ∼4000-bp, and various oligonucleotides lacking the 5'-TTCTA-3' motif at the 3' end of TIR sequence can be integrated efficiently. Furthermore, similar to some Cas1 homologs, the casposase utilizes a 5'-ATAA-3' motif in the TSD as a molecular ruler to dictate nucleophilic attack at 9-bp downstream of the end of the ruler during the spacer-side integration. By characterizing the family 1 Ca. N. koreensis casposase, we have extended our understanding on mechanistic similarities and evolutionary connections between casposons and the adaptation elements of CRISPR-Cas immunity.
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http://dx.doi.org/10.1093/nar/gkab725DOI Listing
August 2021

Phthalates in house dust in Chinese urban residences: Concentrations, partition, origin and determinants.

Chemosphere 2021 Jul 29;286(Pt 2):131703. Epub 2021 Jul 29.

Institute of Built Environment, Department of Building Science, Tsinghua University, Beijing, 100084, China.

Exposure to phthalates poses adverse health impacts to human beings. In this study, we analyzed 7 phthalates in dust samples, which were collected with vacuum cleaner from 40 to 31 residences in Beijing in summer and winter, respectively. The major phthalates (median concentration in the summer and winter, respectively) were DiBP (55 and 40 ng/mg), DnBP (99 and 30 ng/mg) and DEHP (795 and 335 ng/mg). The concentrations were significantly influenced by season and residence time of house dust. The concentrations of phthalates in dust on plastic surfaces were highest, followed by those on wooden and fabric surfaces. The dust-air partition coefficients (K) were calculated: the median values were 0.13, 0.02 and 5.62 m/mg in the summer and 0.06, 0.018 and 0.76 m/mg in the winter for DiBP, DnBP and DEHP, respectively. A comparison with K* at equilibrium state suggested that partition between air and dust deviated from equilibrium state in both seasons. The results also revealed that dust-phthalates in the summer may completely originate from source materials via direct transfer and external physical process; while dust-phthalates in the winter may come from both air (via partition) and source material (via direct transfer and external physical process). The influence of temperature on dust-phthalate concentrations differed by season, owing to different origin of dust-phthalates in two seasons. Polar organic components in dust, which are products of reactions between O and unsaturated hydrocarbons in dust, likely played an important role in fate and transport of phthalates. The presence of them resulted in the significant associations between dust-phthalate concentrations and air humidity in the summer. Moreover, the impacts of indoor PM concentrations, traffic conditions surrounding residence, household lifestyle and number of occupants were also observed. The mechanisms behind those observations were discussed.
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http://dx.doi.org/10.1016/j.chemosphere.2021.131703DOI Listing
July 2021

Improvement of nickel-cobalt-based supercapacitors energy storage performance by modification of elements.

J Colloid Interface Sci 2021 Nov 13;602:712-720. Epub 2021 Jun 13.

School of Physics and Technology, University of Jinan, Shandong 250022, PR China. Electronic address:

Hybrid supercapacitors have the advantages of fast charging and discharging and long service life, which are an efficient and practical energy storage device. Therefore, the design of hybrid supercapacitors is the focus of current research. In this paper, the silver modified spinel NiCoS nanorods (AgS-NiCoS/CF) are synthesized by an efficient and economical method, which has excellent electrochemical performance. The AgS-NiCoS/CF shows a high specific capacity of 179.7 mAh g at current density of 1 A g, and excellent rate capability (capacitance retention of ~87% at 20 A g). The corresponding AgS-NiCoS/CF//AC/CF hybrid supercapacitor is assembled by AgS-NiCoS/CF as the positive electrode, which can provide an energy density of 35.978 Wh kg at a high-power density of 800 W kg and has significant cyclic stability (~80% of the initial capacitor after ~9600 cycles). Therefore, AgS-NiCoS/CF material is a promising electrode material that can be applied to hybrid supercapacitors.
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http://dx.doi.org/10.1016/j.jcis.2021.06.063DOI Listing
November 2021

Paternal Exposure to PM Programs Offspring's Energy Homeostasis.

Environ Sci Technol 2021 05 7;55(9):6097-6106. Epub 2021 Apr 7.

Department of Medicine Cardiology Division, University of Maryland School of Medicine, Baltimore, Maryland 21201, United States.

Considerable studies show that maternal exposure to ambient fine particulate matter (PM) programs offspring's susceptibility to obesity. However, few studies have investigated the effect of paternal PM exposure on offspring's energy homeostasis. This study thus tested whether paternal PM exposure programs offspring's energy homeostasis. Male C57Bl/6J mice were exposed to filtered air or concentrated ambient PM (CAP) for 12 weeks and then mated with normal female C57Bl/6J mice. The offspring were assessed for growth trajectories, food intakes, and body compositions, and the sperm miRNAs of those sires were profiled by microarray. Zygotic injection was used to test whether the miRNA identified by the microarray mediates the impact of paternal PM exposure on offspring's energy homeostasis. Paternal CAP exposure resulted in significant hypophagia and weight loss in male, but not female, offspring. The weight loss of male offspring was accompanied by decreases in the liver and kidney masses and paradoxically an increase in the adipose mass. Without further exposure to CAP, this programming was three-generationally transmitted along the paternal line. The sperm miRNA profiling revealed that mmu-mir6909-5p was the sole differentially expressed sperm miRNA due to PM exposure, and zygotic injection of mmu-mir6909-5p mimicked all the effects of paternal PM exposure on offspring's energy homeostasis. Paternal PM exposure programs offspring's energy homeostasis through increasing paternal sperm mmu-mir6909-5p.
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http://dx.doi.org/10.1021/acs.est.0c08161DOI Listing
May 2021

Effects of nitrogen application rate on the photosynthetic pigment, leaf fluorescence characteristics, and yield of indica hybrid rice and their interrelations.

Sci Rep 2021 Apr 5;11(1):7485. Epub 2021 Apr 5.

College of Agronomy, Guizhou University, Guiyang, 550025, China.

A field experiment employing the rice cultivars Qyou6 and Yixiangyou2115 as materials and different nitrogen application rates was conducted in Huangping County, Guizhou Province in 2019 to determine the effects of nitrogen application rate on photosynthetic pigments, leaf fluorescence characteristics, yield, and their interrelations in indica hybrid rice. The results showed that photosynthetic pigment contents generally increased with increasing nitrogen application rate. As the nitrogen rate increased, the maximal quantum yield of PSII (F/F), actual quantum yield of PSII (Φ), and relative electron transfer rate at PSII (ETR) first decreased and then increased at the booting stage; F/F and Φ decreased while ETR first increased and then decreased at the heading stage; nevertheless, F/F and Φ first decreased and then increased but ETR was just the opposite at the maturity stage. Non-photochemical quenching coefficient (qN) and quantum yield of regulatory energy dissipation at PSII (Y(NPQ)) first increased and then decreased whereas quantum yield of non-regulatory energy dissipation at PSII (Y(NO)) first decreased and then increased at the booting, heading, and maturity stages with increasing nitrogen application rate. Photochemical quenching coefficient (qP) showed an increasing trend as the nitrogen rate increased in the range of 150-300 kg/ha at the heading and maturity stages. Photosynthetic pigments, leaf fluorescence characteristics, and yield and its components were significantly correlated. First, chlorophylls a and b were significantly negatively correlated with F/F while significantly positively correlated with qP at the heading stage. Secondly, Carotenoids were significantly positively correlated with the effective panicle number (EPN) at the booting stage while significantly negatively correlated with the spikelets per panicle (SPP) at the heading stage. Chlorophyll a and carotenoids were significantly positively correlated with EPN but significantly negatively correlated with spikelet filling (SF) at the maturity stage. In addition, qP was significantly negatively correlated with EPN at the booting stage. At the heading stage, F/F and Y(NO) were significantly negatively correlated with EPN and SPP, respectively, and F/F and Φ were significantly positively related to SF. Moreover, qP was extremely significantly positively related to EPN whereas F/F was extremely significantly negatively correlated with grain yield at the maturity stage. Appropriate nitrogen application rates can enhance photosynthetic pigment contents, improve the photochemical efficiency and proportion of the open part of the reaction center of PSII, and promote the quantum efficiency and self-protection ability of PSII, thereby increasing photosynthetic efficiency and yield. Under the conditions adopted in this experiment, a parabolic relationship was observed between the nitrogen application rate and grain yield. The regression analysis results showed that the best nitrogen application rate of indica hybrid rice is 168.16 kg ha and the highest yield is 11,804.87 kg ha.
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http://dx.doi.org/10.1038/s41598-021-86858-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8021548PMC
April 2021

Pavement Overrides the Effects of Tree Species on Soil Bacterial Communities.

Int J Environ Res Public Health 2021 02 23;18(4). Epub 2021 Feb 23.

State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.

Human disturbance and vegetation are known to affect soil microorganisms. However, the interacting effects of pavement and plant species on soil bacterial communities have received far less attention. In this study, we collected soil samples from pine (), ash (), and maple () stands that grew in impervious, pervious, and no pavement blocks to investigate the way pavement, tree species, and their interaction influence soil bacterial communities by modifying soil physicochemical properties. Soil bacterial community composition and diversity were evaluated by bacterial 16S amplicon sequencing. The results demonstrated that soil bacterial community composition and diversity did differ significantly across pavements, but not with tree species. The difference in soil bacterial community composition across pavements was greater in pine stands than ash and maple stands. Soil bacterial diversity and richness indices decreased beneath impervious pavement in pine stands, and only bacterial richness indices decreased markedly in ash stands, but neither showed a significant difference across pavements in maple stands. In addition, bacterial diversity did not differ dramatically between pervious pavement and no pavement soil. Taken together, these results suggest that pavement overwhelmed the effects of tree species on soil bacterial communities, and had a greater effect on soil bacterial communities in pine stands, followed by ash and maple stands. This study highlights the importance of anthropogenic disturbance, such as pavement, which affects soil microbial communities.
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http://dx.doi.org/10.3390/ijerph18042168DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7927126PMC
February 2021

Urbanization's Impacts on Ecosystem Health Dynamics in the Beijing-Tianjin-Hebei Region, China.

Int J Environ Res Public Health 2021 01 21;18(3). Epub 2021 Jan 21.

Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.

Accelerated urbanization disturbs ecosystems and influences ecosystem structures and functions. Ecosystem health (ESH) assessments in regions undergoing the rapid urbanization process assist us in understanding how ESH changes and how urbanization specifically affects ESH. We assessed the ESH of Beijing-Tianjin-Hebei (BTH) region, China, including the ecosystem service value (ESV). In this study, we selected nine indicators and applied multiple pieces of software, including ArcGIS10.4, Fragstats4.2 and Geoda1.14 to detect the impacts of urbanization on regional ESH in 1995, 2000, 2005, 2010 and 2015. The results show that ESH in the BTH region increased from 2000 to 2015, especially in the northern parts. The improvements were due to the implementation of key ecological restoration projects protecting and re-establishing the forest in the north. Furthermore, the spatial correlation results indicate that urbanization had a negative impact on ESH in the BTH region, of which the dominant factor was the population density in 1995. The dominant factor was the construction land proportion from 2005 to 2015. We suggest that ecological restoration projects should be continued in northern regions with strong and relatively strong ESH levels to maintain high-level ecosystem health. In addition, more attention should be paid to the ESH level improvement in peri-urban areas.
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http://dx.doi.org/10.3390/ijerph18030918DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7908245PMC
January 2021

A Mini Review of the Preparation and Photocatalytic Properties of Two-Dimensional Materials.

Front Chem 2020 9;8:582146. Epub 2020 Dec 9.

Laboratory of Functional Micro and Nano Materials and Devices, School of Physics and Technology, University of Jinan, Jinan, China.

The successful preparation and application of graphene shows that it is feasible for the materials with a thickness of a single atom or few atomic layers to exist stably in nature. These materials can exhibit unusual physical and chemical properties due to their special dimension effects. At present, researchers have made great achievements in the preparation, characterization, modification, and theoretical research of 2D materials. Because the structure of 2D materials is often similar, it has a certain degree of qualitative versatility. Besides, 2D materials often carry good catalytic performance on account of their more active sites and adjustable harmonic electronic structure. In this review, taking 2D materials as examples [graphene, boron nitride (h-BN), transition metal sulfide and so on], we review the crystal structure and preparation methods of these materials in recent years, focus on their photocatalyst properties (carbon dioxide reduction and hydrogen production), and discuss their applications and development prospects in the future.
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http://dx.doi.org/10.3389/fchem.2020.582146DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7755974PMC
December 2020

Selection and validation of reference genes for qRT-PCR analysis during fruit ripening of red pitaya (Hylocereus polyrhizus).

FEBS Open Bio 2020 Dec 2. Epub 2020 Dec 2.

Institute of Pomology Science, Guizhou Provincial Academy of Agricultural Sciences.

Red pitaya (Hylocereus polyrhizus) is widely cultivated in southern and southwestern China. To provide a basis for studying the molecular mechanisms of the ripening of this fruit, we carried out RNA-seq analysis to identify differentially and stably expressed unigenes. The latter may serve as a resource of potential reference genes for normalization of target gene expression determined using qRT-PCR. We selected 11 candidate reference genes from our RNA-seq analysis of red pitaya fruit ripening (ACT7, EF-1α, IF-4α, PTBP, PP2A, EF2, Hsp70, GAPDH, DNAJ, TUB and CYP), as well as β-ACT, which has been used as a reference gene for pitayas in previous studies. We then comprehensively evaluated their expression stability during fruit ripening using four statistical methods (GeNorm, NormFinder, BestKeeper and DeltaCt), and merged the four outputs using the online tool RefFinder for the final ranking. We report that PTBP and DNAJ showed the most stable expression patterns, while CYP and ACT7 showed the least stable expression patterns. The relative gene expression of red pitaya sucrose synthase and 4, 5-DOPA-extradiol-dioxygenase as determined by qRT-PCR and normalized to PTBP and DNAJ were consistent with the RNA-seq results, suggesting that PTBP and DNAJ are suitable reference genes for studies of red pitaya fruit ripening.
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http://dx.doi.org/10.1002/2211-5463.13053DOI Listing
December 2020

The effects of antimony on Alzheimer's disease-like pathological changes in mice brain.

Sci Total Environ 2021 Mar 26;760:143235. Epub 2020 Oct 26.

Department of Occupational Medicine and Environmental Toxicology, School of Public Health, Nantong University, Nantong 226019, China. Electronic address:

We have previously identified antimony (Sb) as a newly nerve poison which leads to neuronal apoptosis. However, the relationship between Sb exposure and Alzheimer's disease (AD) process lacks direct evidence. HE staining and Nissl staining showed significant nerve damage after Sb exposure. Therefore, we further evaluated Sb-associated AD risk by detecting accumulation of β-amyloid protein (Aβ) and neurofibrillary tangles (NFTs) in the brains of mice exposed to Sb for 4 and 8 weeks, and even 1 year. The results showed that dose of 20 mg/kg induced Aβ accumulation, but not tau hyperphosphorylation after exposure for 4 week. Eight weeks later, both 10 and 20 mg/kg dramatically triggered Aβ accumulation and increased tau phosphorylation at ser199. At the same time, 20 mg/kg could also increase tau phosphorylation at ser396 and number of NFTs. One years later, we found all of AD hallmarks detected in present study showed positive results in the brains of mice exposed to Sb at 10 and 20 mg/kg. In summary, our data provided direct evidence of Sb-associated AD risk, drawing more attention to Sb-triggered neurotoxicity.
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http://dx.doi.org/10.1016/j.scitotenv.2020.143235DOI Listing
March 2021

Design of nickel cobalt molybdate regulated by boronizing for high-performance supercapacitor applications.

Nanoscale 2020 Sep 25;12(34):17849-17857. Epub 2020 Aug 25.

Laboratory of Functional Micro-nano Materials and Devices, School of Physics and Technology, University of Jinan, Jinan 250022, P. R. China.

Nickel-cobalt-based molybdates have been intensively investigated because of their high theoretical specific capacitance and multifarious oxidation states. Here, we have successfully synthesized hierarchical structures (NiB/Ni(BO)@NiCoMoO) by boronizing NiCoMoO nanosheets on flexible carbon cloth substrates. Benefitting from the synergistic effect among NiB, Ni(BO) and NiCoMoO in hybrid architectures, the electrode material possesses higher capacity of 394.7 mA h g at 1 A g and a good rate performance (309.5 mA h g maintained at 20 A g). Then, a hybrid supercapacitor assembled with NiB/Ni(BO)@NiCoMoO and activated carbon as the positive and the negative electrode, displays a high specific capacitance of 370.7 F g at 1 A g (210 F g at 10 A g), a high voltage of 1.7 V, and a high energy density of 131.8 W h kg at the power density of 800 W kg (still 74.7 W h kg maintained at 8000 W kg). This study widens the research scope of boronizing pseudocapacitance materials and reveals a high application potential of NiB/Ni(BO)@NiCoMoO for energy storage devices in the future.
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http://dx.doi.org/10.1039/d0nr05377eDOI Listing
September 2020

Increased greenhouse gas emissions intensity of major croplands in China: Implications for food security and climate change mitigation.

Glob Chang Biol 2020 Nov 2;26(11):6116-6133. Epub 2020 Sep 2.

Department of Forestry, Mississippi State University, Mississippi State, MS, USA.

Balancing crop production and greenhouse gas (GHG) emissions from agriculture soil requires a better understanding and quantification of crop GHG emissions intensity, a measure of GHG emissions per unit crop production. Here we conduct a state-of-the-art estimate of the spatial-temporal variability of GHG emissions intensities for wheat, maize, and rice in China from 1949 to 2012 using an improved agricultural ecosystem model (Dynamic Land Ecosystem Model-Agriculture Version 2.0) and meta-analysis covering 172 field-GHG emissions experiments. The results show that the GHG emissions intensities of these croplands from 1949 to 2012, on average, were 0.10-1.31 kg CO -eq/kg, with a significant increase rate of 1.84-3.58 × 10  kg CO -eq kg  year . Nitrogen fertilizer was the dominant factor contributing to the increase in GHG emissions intensity in northern China and increased its impact in southern China in the 2000s. Increasing GHG emissions intensity implies that excessive fertilizer failed to markedly stimulate crop yield increase in China but still exacerbated soil GHG emissions. This study found that overfertilization of more than 60% was mainly located in the winter wheat-summer maize rotation systems in the North China Plain, the winter wheat-rice rotation systems in the middle and lower reaches of the Yangtze River and southwest China, and most of the double rice systems in the South. Our simulations suggest that roughly a one-third reduction in the current N fertilizer application level over these "overfertilization" regions would not significantly influence crop yield but decrease soil GHG emissions by 29.60%-32.50% and GHG emissions intensity by 0.13-0.25 kg CO -eq/kg. This reduction is about 29% and 5% of total agricultural soil GHG emissions in China and the world, respectively. This study suggests that improving nitrogen use efficiency would be an effective strategy to mitigate GHG emissions and sustain China's food security.
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http://dx.doi.org/10.1111/gcb.15290DOI Listing
November 2020

Stability and applicability of the leaf value model for variable nitrogen application based on SPAD value in rice.

PLoS One 2020 4;15(6):e0233735. Epub 2020 Jun 4.

College of Agronomy, Guizhou University, Guiyang, China.

Many fertilization models have been created to scientifically determine the amount of fertilization. With the same purpose, we constructed a nitrogen (N) application model, the leaf value model, which can make N fertilizer decisions in a timely, fast and nondestructive manner during rice planting. However, only one area (A1, Jiuzhou Town, Xixiu District, Guizhou Province) and one cultivar (Qyou6) were involved in the construction of the leaf value model. Its stability and applicability could not be well evaluated. Thus, we chose another area (A2, Jiuzhou Town, Huangping County, Guizhou Province) in Guizhou Province and carried out the experiment by using four cultivars (Nie5you5399, Qyou6, Yixiangyou2115 and Zhongzheyou8) for the leaf value model construction. Compared with the average value of apparent total N uptake (Nz) obtained in 2 years in the A1 area, that in the Qyou6 leaf value model in the A2 area increased by 12%, reaching 635.72 kg ha-1, whereas the corresponding target yield changed slightly, reaching 10,999.90 kg ha-1. Simultaneously, the linear relationship between several good SPAD value-derived indexes (Ys) and apparent N supply of the field (Nx) was still significant or extremely significant in the Qyou6 leaf value model. Compared with the A1 area, it slightly differed, and the R2 of SPADL1 was higher than that of SPADL3×L4/mean. In the leaf value model of the other three cultivars, the relationship between yield and Nx and that between Ys and Nx were significant or extremely significant. The Nz of Yixiangyou2115 and Zhongzheyou8 (618.33 and 617.76 kg ha-1) were close to that of Qyou6 and the corresponding target yields were 10313.36 and 10301.99 kg ha-1, respectively. The Nz and target yield of Nie5you5399 were lowest at 546.63 and 10680.24 kg ha-1, respectively. In general, this study showed that relationships used in the construction of leaf value model had certain stability and applicability to difference areas and cultivars. The leaf value model can be considered in N fertilizer decision-making of rice planting management.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0233735PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7272043PMC
August 2020

Factors responsible for forest and water bird distributions in rivers and lakes along an urban gradient in Beijing.

Sci Total Environ 2020 Sep 12;735:139308. Epub 2020 May 12.

State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049,China. Electronic address:

Urban rivers and lakes, in combination with nearby green spaces, provide important habitat for urban birds, but few urban studies have focused on forest and water birds simultaneously along an urban intensity gradient. In this study, we randomly chose 39 rivers and lakes along an urban gradient of Beijing to examine bird community parameters in relation to aquatic and terrestrial habitat conditions, aquatic life data, and water quality data. We selected models with the AICc (corrected Akaike information criterion) method, bivariate linear or generalized linear regressions, and structural equation modeling to determine distribution patterns of avian communities along an urban gradient and bird-environment relationships. We found that both forest and water bird species and individuals peaked at intermediate urbanization intensities, especially for abundance of both forest and water bird and water bird species richness and abundance. We suggest that the differences in the strength of response to urbanization and the similarities in the gradient distribution pattern between forest and water birds should receive more attention in future urbanization gradient studies. Significant correlation ship between species richness of resident water birds, fish foragers, and insectivore-frugivores, abundance of insectivores, insectivore-frugivores (negative), and granivores (positive) and impervious surface proportion within 1-km radius buffer of sampled sites became more evident after coverage of artificial surfaces exceeded a 50% threshold. Regressions showed that distance from the urban center, number of islands in waterbody, and proportion of gross or unarmored shoreline length were significantly and positively related to species richness and abundance of both forest and water birds. The availability of unarmored shoreline is a critical pathway through which urbanization detrimentally impacts avian diversity. Our results demonstrate how the urban intensity gradient affects the relative availability of food resources and habitat, which could provide practical applications for urban landscape planning and avian biodiversity conservation in urban areas.
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http://dx.doi.org/10.1016/j.scitotenv.2020.139308DOI Listing
September 2020

p62/SQSTM1 accumulation due to degradation inhibition and transcriptional activation plays a critical role in silica nanoparticle-induced airway inflammation via NF-κB activation.

J Nanobiotechnology 2020 May 19;18(1):77. Epub 2020 May 19.

Department of Occupational Medicine and Environmental Toxicology, School of Public Health, Nangtong University, Nantong, 226019, China.

Background: Most nanoparticles (NPs) reportedly block autophagic flux, thereby upregulating p62/SQSTM1 through degradation inhibition. p62 also acts as a multifunctional scaffold protein with multiple domains, and is involved in various cellular processes. However, the autophagy substrate-independent role of p62 and its regulation at the transcriptional level upon NPs exposure remain unclear.

Results: In this work, we exposed BEAS-2b cells and mice to silica nanoparticles (SiNPs), and found that SiNPs increased p62 protein levels in vivo and vitro. Then, we further explored the role and mechanism of SiNPs-stimulated p62 in vitro, and found that p62 degradation was inhibited due to autophagic flux blockade. Mechanistically, SiNPs blocked autophagic flux through impairment of lysosomal capacity rather than defective autophagosome fusion with lysosomes. Moreover, SiNPs stimulated translocation of NF-E2-related factor 2 (Nrf2) to the nucleus from the cytoplasm, which upregulated p62 transcriptional activation through direct binding of Nrf2 to the p62 promoter. Nrf2 siRNA dramatically reduced both the mRNA and protein levels of p62. These two mechanisms led to p62 protein accumulation, thus increasing interleukin (IL)-1 and IL-6 expression. SiNPs activated nuclear factor kappa B (NF-κB), and this effect could be alleviated by p62 knockdown.

Conclusion: SiNPs caused accumulation of p62 through both pre- and post-translational mechanisms, resulting in airway inflammation. These findings improve our understanding of SiNP-induced pulmonary damage and the molecular targets available to mitigate it.
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http://dx.doi.org/10.1186/s12951-020-00634-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7236097PMC
May 2020

Motion-robust, high-SNR liver fat quantification using a 2D sequential acquisition with a variable flip angle approach.

Magn Reson Med 2020 10 3;84(4):2004-2017. Epub 2020 Apr 3.

Department of Radiology, University of Wisconsin-Madison, Madison, WI, USA.

Purpose: Chemical shift encoded (CSE)-MRI enables quantification of proton-density fat fraction (PDFF) as a biomarker of liver fat content. However, conventional 3D Cartesian CSE-MRI methods require breath-holding. A motion-robust 2D Cartesian sequential method addresses this limitation but suffers from low SNR. In this work, a novel free breathing 2D Cartesian sequential CSE-MRI method using a variable flip angle approach with centric phase encoding (VFA-centric) is developed to achieve fat quantification with low bias, high SNR, and minimal blurring.

Methods: Numerical simulation was performed for variable flip angle schedule design and preliminary evaluation of VFA-centric method, along with several alternative flip angle designs. Phantom, adults (n = 8), and children (n = 27) were imaged at 3T. Multi-echo images were acquired and PDFF maps were estimated. PDFF standard deviation was used as a surrogate for SNR.

Results: In both simulation and phantom experiments, the VFA-centric method enabled higher SNR imaging with minimal bias and blurring artifacts. High correlation (slope = 1.00, intercept = 0.04, = 0.998) was observed in vivo between the proposed VFA-centric method obtained PDFF and reference PDFF (free breathing low-flip angle 2D sequential acquisition). Further, the proposed VFA-centric method (PDFF standard deviation = 1.5%) had a better SNR performance than the reference acquisition (PDFF standard deviation = 3.3%) with P < .001.

Conclusions: The proposed free breathing 2D Cartesian sequential CSE-MRI method with variable flip angle approach and centric-ordered phase encoding achieved motion robustness, low bias, high SNR compared to previous 2D sequential methods, and low blurring in liver fat quantification.
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http://dx.doi.org/10.1002/mrm.28263DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7366366PMC
October 2020

Complete genome sequence of a new member of the genus Badnavirus from red pitaya (Hylocereus polyrhizus).

Arch Virol 2020 Mar 7;165(3):749-752. Epub 2020 Feb 7.

Institute of Pomology Science, Guizhou Provincial Academy of Agricultural Sciences, Huaxi District, Jinzhu Town, Guiyang, 550006, Guizhou, China.

Here, we report a circular double-stranded DNA virus from red pitaya (Hylocereus polyrhizus). The complete genome sequence is 7,837 nt in length and shares 98.7% nucleotide sequence identity with epiphyllum mottle-associated virus (EpMoaV) and 40.4-54.6% with other members of the genus Badnavirus. It has four open reading frames (ORFs), encoding putative proteins of 19.9, 14.8, 225.7 and 14.2 kDa, respectively. The reverse transcriptase (RT)-ribonuclease H (RNase H) region exhibits less than 70.5% nucleotide sequence identity to RT-RNase H of other badnaviruses, and 99.7% to that of EpMoaV. Phylogenetic analysis revealed that the virus from this study and EpMoaV form a single group. Consequently, we propose this virus as a new member of the genus Badnavirus in the family Caulimoviridae and have named it "pitaya badnavirus 1" (PiBV1). PiBV1 and EpMoaV should be considered two isolates of a badnavirus that infects members of the family Cactaceae.
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http://dx.doi.org/10.1007/s00705-019-04503-7DOI Listing
March 2020

Phase-based T mapping with gradient echo imaging.

Magn Reson Med 2020 08 24;84(2):609-619. Epub 2019 Dec 24.

Department of Radiology, University of Wisconsin, Madison, Wisconsin.

Purpose: Transverse relaxation time (T ) mapping with MRI has a plethora of clinical and research applications. Current T mapping techniques are based primarily on spin-echo (SE) relaxometry strategies that rely on the signal magnitude, and often suffer from lengthy acquisition times. In this work, we propose a phase-based T mapping technique where T information is encoded into the signal phase of rapid gradient echo (GRE) acquisitions.

Theory: Bloch equation simulations demonstrate that the phase of GRE acquisitions obtained with a very small inter-repetition RF phase increment has a strong monotonic dependence on T , resulting from coherent transverse magnetization. This T -dependent phase behavior forms the basis of the proposed T mapping technique. To isolate T -dependent phase from background phase, at least 2 data sets with different RF phase increments are acquired. The proposed method can also be combined with chemical shift encoded MRI to separate water and fat signals.

Methods: The feasibility of the proposed technique was validated in a phantom experiment. In vivo feasibility was demonstrated in the brain, knee, abdomen, and pelvis. Comparisons were made with SE-based T mapping, spectroscopy, and T values from the literature.

Results: The proposed method produced accurate T maps compared with SE-based T mapping in the phantom. Good qualitative agreement was observed in vivo between the proposed method and the reference. T measured in various anatomies agreed well with values reported in the literature.

Conclusion: A phase-based T mapping technique was developed and its feasibility demonstrated in phantoms and in vivo.
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http://dx.doi.org/10.1002/mrm.28138DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7180093PMC
August 2020

Novel mulberry silkworm cocoon-derived carbon dots and their anti-inflammatory properties.

Artif Cells Nanomed Biotechnol 2020 Dec;48(1):68-76

School of Preclinical Medicine, Beijing Key Laboratory, Beijing University of Chinese Medicine, Beijing, China.

Mulberry silkworm cocoon (MSC) carbonisata has been used for the treatment of inflammatory diseases for hundreds of years; however, after years of research efforts, little information is available on its anti-inflammatory components and underlying mechanism. We developed novel carbon dots (CDs) derived from MSC carbonisata (MSC-CDs), for the first time, with an average diameter of 2.26-9.35 nm and a quantum yield (QY) of 6.32%. The MSC-CDs were prepared using a modified pyrolysis method, and no further modification and external surface passivation agent was required. With abundant surface groups, MSC-CDs showed distinct solubility and bioactivity. In this study, we innovatively used three classical experimental models of inflammation to evaluate the anti-inflammatory bioactivity of MSC-CDs. The results indicated that MSC-CDs exhibited marked anti-inflammatory bioactivity which was likely mediated by inhibition of the expression of interleukin-6 and tumour necrosis factor-α. These results suggest that MSC-CDs possess a remarkable anti-inflammatory property, which provides evidence to support further investigation of the considerable potential and effective material basis of this traditional Chinese medicine.
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http://dx.doi.org/10.1080/21691401.2019.1699810DOI Listing
December 2020

Protective Effects of Carbon Dots Derived from Phellodendri Chinensis Cortex Carbonisata against Deinagkistrodon acutus Venom-Induced Acute Kidney Injury.

Nanoscale Res Lett 2019 Dec 16;14(1):377. Epub 2019 Dec 16.

Center of Scientific Experiment, Beijing University of Chinese Medicine, Beijing, 100029, China.

Background: As an emerging nanomaterial, carbon dots (CDs) have been the focus of tremendous attention for biomedical applications. However, little information is available on their bioactivity of inhibiting acute kidney injury (AKI) induced by snake venom.

Methods: This study reports the development of a green, one-step pyrolysis process to synthesize CDs using Phellodendri Chinensis Cortex (PCC) as the sole precursor, and their potential application as a protectant against Deinagkistrodon acutus (D. acutus) venom-induced AKI was investigated for the first time. The AKI model was established by injecting D. acutus venom into the abdominal cavity of mice and the potential protective effects of PCC Carbonisata-CDs (PCCC-CDs) on renal abnormalities including dysfunction, inflammatory reactions, tissue damage, and thrombocytopenia at six time points (1, 3, and 12 h, and 1, 2, and 5 days) were investigated.

Results: These results demonstrated that PCCC-CDs significantly inhibited the kidney dysfunction (reduced serum creatinine (SCR), blood urea nitrogen (BUN), urinary total protein (UTP), and microalbuminuria (MALB) concentrations) and the production of chemoattractant (monocyte chemotactic protein 1 (MCP-1)), proinflammatory cytokines (interleukin (IL)-1β), and anti-inflammatory cytokine (IL-10) in response to intraperitoneal injection of D. acutus venom. The beneficial effect of PCCC-CDs on the envenomed mice was similar to that on the change in renal histology and thrombocytopenia.

Conclusions: These results demonstrated the remarkable protective effects of PCCC-CDs against AKI induced by D. acutus venom, which would not only broaden the biomedical applications of CDs but also provide a potential target for the development of new therapeutic drugs for AKI induced by D. acutus snakebite envenomation.
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http://dx.doi.org/10.1186/s11671-019-3198-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6915193PMC
December 2019

Hierarchical porous structured polysulfide supported nZVI/biochar and efficient immobilization of selenium in the soil.

Sci Total Environ 2020 Mar 3;708:134831. Epub 2019 Nov 3.

State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, PR China.

Soil pollution with selenium is a significant environmental problem in several areas of the world, which extremely affects the growth of plants and human health. Thus, it is necessary to find an effective method to immobilize selenium in the soil to make it less bioavailable and less accessible. In this study, the low-cost biochar-supported nanoscale zero-valent iron and polysulfide ([email protected]) are produced and used for the immobilization of selenium (Se) in soil. The FTIR, UV-Vis, XRD, VSM, SEM and XPS techniques validate surface properties and morphology of [email protected] Introduction of S led to the in-situ formation of FeS on the surface of the biochar supported zero valent iron. Two intense Bragg peaks (2θ) of 40.5°, 44.5° were corresponded to Fe basal plane, indicating the presence of nZVI in [email protected] and [email protected] The modified biochar presents a magnetic saturation value of 0.008 emu/mg, reasonably less than the reported values of bare nZVI. The soil immobilization showed that the [email protected] is more effective for the control of selenium than the biochar and [email protected] The available selenium content decreased by 77.29% in [email protected] amended soil after 30 days. From sequential extraction procedure (SEP) results, it was observed that [email protected] promoted the conversion of more accessible Se (water-soluble and exchangeable fractions) into the less accessible forms (acid-soluble, organic, and residual fractions) to reduce the toxicity of Se. Surface sorption, reduction and complexation were dominant mechanisms for Se immobilization. Hence, [email protected] is promising and effective for immobilizing Se in contaminated soils and improving the soil properties.
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http://dx.doi.org/10.1016/j.scitotenv.2019.134831DOI Listing
March 2020

Novel Carbon Dots Derived from Radix and Their Anti-Gout Effects.

Molecules 2019 Nov 16;24(22). Epub 2019 Nov 16.

School of Preclinical Medicine, Beijing Key Laboratory, Beijing University of Chinese Medicine, Beijing 100102, China.

Gout is a disease with a high incidence and causing great harm, and the current treatment drugs are not satisfactory. In this study, novel water-soluble carbon dots (CDs) with anti-gout effect, named Radix CDs (PLR-CDs), are reported. PLR-CDs were synthesized with an improved pyrolysis method at 300 °C, and their characterization was performed with multifaceted approaches, such as transmission electron microscopy (TEM) and ultraviolet-visible (UV-vis) and Fourier-transform infrared (FTIR) spectroscopy. In addition, the biocompatibility of PLR-CDs was studied using the cell counting kit (CCK)-8 in LO2 cells and RAW264.7 cells, and the anti-gout activity of PLR-CDs was examined on animal models of hyperuricemia and gouty arthritis. The characterization of PLR-CDs indicated that they were nearly spherical, with diameters ranging from 3.0 to 10.0 nm, and the lattice spacing was 0.283 nm. The toxicity experiment revealed that PLR-CDs were non-poisonous for LO2 cells and RAW264.7 cells at concentrations below 250 μg/mL. The results of pharmacodynamic experiments showed that PLR-CDs could lower the blood uric acid level in model rats by inhibiting the activity of xanthine oxidase and reduce the degree of swelling and pathological damage of gouty arthritis. Thus, PLR-CDs with anti-gout biological activity and good biocompatibility have the prospect of clinical application for the treatment of gout.
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http://dx.doi.org/10.3390/molecules24224152DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6891613PMC
November 2019

T -corrected quantitative chemical shift-encoded MRI.

Magn Reson Med 2020 06 14;83(6):2051-2063. Epub 2019 Nov 14.

Department of Radiology, University of Wisconsin, Madison, Wisconsin.

Purpose: To develop and validate a T -corrected chemical-shift encoded MRI (CSE-MRI) method to improve noise performance and reduce bias for quantification of tissue proton density fat-fraction (PDFF).

Methods: A variable flip angle (VFA)-CSE-MRI method using joint-fit reconstruction was developed and implemented. In computer simulations and phantom experiments, sources of bias measured using VFA-CSE-MRI were investigated. The effect of tissue T on bias using low flip angle (LFA)-CSE-MRI was also evaluated. The noise performance of VFA-CSE-MRI was compared to LFA-CSE-MRI for liver fat quantification. Finally, a prospective pilot study in patients undergoing gadoxetic acid-enhanced MRI of the liver to evaluate the ability of the proposed method to quantify liver PDFF before and after contrast.

Results: VFA-CSE-MRI was accurate and insensitive to transmit B inhomogeneities in phantom experiments and computer simulations. With high flip angles, phase errors because of RF spoiling required modification of the CSE signal model. For relaxation parameters commonly observed in liver, the joint-fit reconstruction improved the noise performance marginally, compared to LFA-CSE-MRI, but eliminated T -related bias. A total of 25 patients were successfully recruited and analyzed for the pilot study. Strong correlation and good agreement between PDFF measured with VFA-CSE-MRI and LFA-CSE-MRI (pre-contrast) was observed before (R = 0.97; slope = 0.88, 0.81-0.94 95% confidence interval [CI]; intercept = 1.34, -0.77-1.92 95% CI) and after (R = 0.93; slope = 0.88, 0.78-0.98 95% CI; intercept = 1.90, 1.01-2.79 95% CI) contrast.

Conclusion: Joint-fit VFA-CSE-MRI is feasible for T -corrected PDFF quantification in liver, is insensitive to B inhomogeneities, and can eliminate T bias, but with only marginal SNR advantage for T values observed in the liver.
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http://dx.doi.org/10.1002/mrm.28062DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7047527PMC
June 2020

The effect of habitat changes along the urbanization gradient for breeding birds: an example from the Xiong'an New Area.

PeerJ 2019 30;7:e7961. Epub 2019 Oct 30.

State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-environmental Science, Chinese Academy of Sciences, Beijing, People's Republic of China.

Background: Because of its status as an ecocivilization pilot city, fundamental research on spatial distribution patterns and impact factors of the avian community within the Xiong'an New Area is necessary for future ecological planning and mitigation of negative impacts from future urbanization. Gradient research within small cities can provide important information for the development of urbanization gradient patterns of avian communities.

Methods: A total of 30 sample points within the urbanization gradient were selected, and avian communities and environmental variables were measured within a 50 m radius sample circle. Principal component regression analysis was used to analyze bird-environment relationships. The Sorensen dissimilarity index was used to calculate the beta-diversity.

Results: Our results showed that there was a significant urban-rural pattern with a gradient phenomenon in avian communities. Results of this study showed more resident, passenger and insectivore species, and a higher density of breeding insectivore and omnivore individuals appear in the urban fringe than in the other areas. A relatively high value of overall beta-diversity and spatial isolation probably exists among the three disjunct constructed regions. Both species richness and individual abundance were significantly influenced by the species diversity of the trees and foliage height diversity (FHD).

Discussion: Based on our results and our goal of avian species diversity conservation, we first suggest that urban green spaces be established and ensure a high complexity of vegetation structure as this is critically needed to increase avian species -diversity within habitat patches. Second, different habitat types within and around the three constructed areas should be developed based on the important existing bird habitats to increase avian diversity in each city, especially in the areas within Xiongxian and Rongcheng that are well protected, and to elevate the beta-diversity of the total region. Finally, based on the biodiversity hotspots identified by this research, ecological corridors should be carefully planned to improve the stability of regional bird communities.
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http://dx.doi.org/10.7717/peerj.7961DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6825411PMC
October 2019

Effects of Elevated CO on Leaf Senescence, Leaf Nitrogen Resorption, and Late-Season Photosynthesis in L.

Front Plant Sci 2019 18;10:1217. Epub 2019 Oct 18.

Stockbridge School of Agriculture, University of Massachusetts, Amherst, MA, United States.

We investigated the effects of elevated CO concentrations ([CO]) on autumnal leaf falling, late-season photosynthesis, and leaf N resorption efficiency by exposing L. to three CO levels (800 ppm A8, 600 ppm A6, and ambient air A4) in nine continuous stirred tank reactors (CSTRs). All leaves were subdivided into the first (Z1), second (Z2), and third bud break (Z3) leaves. Whole plant photosynthesis (P) was determined by summing the products of P and total leaf area in Z1, Z2, and Z3, respectively. The results indicated that 1) the timing of leaf senescence in A8 treatments was 21 days in advance, while the senescence duration sustained 20 days longer than ambient treatment; 2) elevated [CO] significantly induced the early formation of overwintering buds, with the number increased by 42 and 29% in A8 and A6 treatments, respectively; 3) Z3 leaf photosynthesis increases consistently until the end of the growing season, but Z2 leaves and whole plant showed acclimation when senescence happened; and 4) autumnal N resorption efficiency in A8 and A6 leaves were 25.5% and 22.7% higher than A4, respectively. In conclusion, autumnal senescence of was accelerated, while the leaf falling duration was extended by elevated [CO]. The change in leaf phenology makes higher N resorption efficiency and earlier and more winter bud formation possible. Meanwhile, a different response of P within different bud break leaves leads to the disparity between instantaneous measurements of leaf photosynthesis and whole plant photosynthesis in end season.
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http://dx.doi.org/10.3389/fpls.2019.01217DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6813238PMC
October 2019

Prenatal exposure to diesel exhaust PM programmed non-alcoholic fatty liver disease differently in adult male offspring of mice fed normal chow and a high-fat diet.

Environ Pollut 2019 Dec 11;255(Pt 1):113366. Epub 2019 Oct 11.

Department of Occupational Medicine and Environmental Toxicology, School of Public Health, Nantong University, Nantong, 226019, China. Electronic address:

Air pollution is one of the leading preventable threats to public health. Emerging evidence indicates that exposure to environmental stressors is associated with abnormal foetal development. However, how prenatal exposure to diesel exhaust PM (DEP) predisposes adult offspring to the development of non-alcoholic fatty liver disease (NAFLD) remains unclear. To examine this, C57BL/6J mice were exposed to DEP or a vehicle before conception and during pregnancy and fed normal chow or a high-fat diet. Then, the hepatic fatty accumulation in the adult male offspring and possible molecular mechanisms were assessed. Our data showed that prenatal exposure to DEP on normal chow led to hepatic steatosis in adult male offspring with normal liver function. However, prenatal DEP exposure relieved the hepatic steatosis and liver function in offspring of mice fed a high-fat diet. Furthermore, prenatal exposure to DEP on normal chow increased lipogenesis and worsened fatty acid oxidation. The counteractive effect of prenatal DEP exposure on high-fat-diet-induced hepatic steatosis was produced through upregulated adenosine 5'-monophosphate-activated protein kinase, and this improved lipogenesis and fatty acid oxidation. Collectively, prenatal exposure to DEP programmed the development of NAFLD differently in the adult male offspring of mice fed normal chow and a high-fat diet, showing the pleotrophic effects of exposure to adverse environmental factors in early life.
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http://dx.doi.org/10.1016/j.envpol.2019.113366DOI Listing
December 2019

Combined gadoxetic acid and gadobenate dimeglumine enhanced liver MRI: a parameter optimization study.

Abdom Radiol (NY) 2020 01;45(1):220-231

Department of Radiology, University of Wisconsin - School of Medicine and Public Health, 1111 Highland Avenue, Madison, WI, 53705, USA.

Purpose: To demonstrate the feasibility of combined delayed-phase gadoxetic acid (GA) and gadobenate dimeglumine (GD) enhanced liver MRI for improved detection of liver metastases, and to optimize contrast agent dose, timing, and flip angle (FA).

Methods: Fourteen healthy volunteers underwent liver MRI at 3.0T at two visits during which they received two consecutive injections: 1. GA (Visit 1 = 0.025 mmol/kg; Visit 2 = 0.05 mmol/kg) and 2. GD (both visits = 0.1 mmol/kg) 20 min after GA administration. Two sub-studies were performed: Experiment-1 Eight subjects underwent multi-phase breath-held 3D-fat-saturated T1-weighted spoiled gradient echo (SGRE) imaging to determine the optimal imaging window for the combined GA + GD protocol to create a homogeneously hyperintense liver and vasculature ("plain-white-liver") with maximum contrast to muscle which served as a surrogate for metastatic lesions in both experiments. Experiment-2 Six subjects underwent breath-held 3D-fat-saturated T1-weighted SGRE imaging at three different FA to determine the optimal FA for best image contrast. Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were evaluated.

Results: Experiment-1 The combined GA + GD protocol created a homogeneously hyperintense liver and vasculature with maximum CNR liver/muscle at approximately 60-120 s after automatic GD-bolus detection. Experiment-2 Flip angles between 25° and 35° at a dose of 0.025 mmol/kg GA provided the best combination that minimized liver/vasculature CNR, while maximizing liver/muscle CNR. CNR performance to achieve a "plain-white-liver" was superior with 0.025 mmol/kg GA compared to 0.05 mmol/kg.

Conclusion: Combined GA + GD enhanced T1-weighted MRI is feasible to achieve a homogeneously "plain-white-liver". Future studies need to confirm that this protocol can improve sensitivity of liver lesion detection in patients with metastatic liver disease.
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http://dx.doi.org/10.1007/s00261-019-02265-zDOI Listing
January 2020
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