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1.
Dev Comp Immunol ; 102: 103468, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31430488

RESUMO

Insects, which lack the adaptive immune system, have developed sophisticated innate immune system consisting of humoral and cellular immune responses to defend against invading microorganisms. Non-self recognition of microbes is the front line of the innate immune system. Repertoires of pattern recognition receptors (PRRs) recognize the conserved pathogen-associated molecular patterns (PAMPs) present in microbes, such as lipopolysaccharide (LPS), peptidoglycan (PGN), lipoteichoic acid (LTA) and ß-1, 3-glucans, and induce innate immune responses. In this review, we summarize current knowledge of the structure, classification and roles of PRRs in innate immunity of the model organism Drosophila melanogaster, focusing mainly on the peptidoglycan recognition proteins (PGRPs), Gram-negative bacteria-binding proteins (GNBPs), scavenger receptors (SRs), thioester-containing proteins (TEPs), and lectins.

2.
Sci Total Environ ; 698: 134229, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31505341

RESUMO

Polycyclic aromatic hydrocarbons (PAHs) in the environment are of significant concerns due to their high toxicity to human health. PAHs measurements at limited air quality monitoring stations alone are insufficient to gain a complete understanding of ambient levels and public exposure of PAHs in China. This study simulated the concentrations of PAHs in China, identified the source contributions, and estimated the health risks. Anthropogenic emissions of 16 priority PAHs directly associated with health risks were generated from the global high-resolution PKU-FUEL-2007 inventory. Open biomass burning emissions were generated from the Fire Inventory from NCAR (FINN). PAHs concentrations in January, April, July, and October 2013 were simulated using the Community Multiscale Air Quality (CMAQ) model after incorporation of chemistry, partitioning, and deposition of PAHs. Predicted PAHs were in good agreement with seasonal and annual averaged observations from previous studies. The surface concentrations of 16-PAHs were higher in winter, with population weight average of 0.8 µg/m3 and peak value of 2.0 µg/m3 in urban areas in the North China Plain (NCP) and the Yangtze River Delta (YRD). Summer and spring exhibited lower concentrations of approximately 0.2 µg/m3 in most areas. The most important sources to PAHs were biomass burning and coal combustion in winter and industrial processes and oil and gas activities in summer. The cancer risk due to inhalation exposure of naphthalene (NAPH) and seven carcinogenic PAHs was significant, with the incremental lifetime cancer risk (ILCR) of >5 × 10-4 in many urban and industrial areas. Exposure to PAHs was estimated to result in 15,198 excess lifetime cancer cases in China. Oil and gas burning associated with transport, residential and commercial activities were major contributors to ILCR in China. Coal combustion was predominant in Shanxi but less important in other regions.

3.
Virology ; 539: 114-120, 2020 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-31710910

RESUMO

Like their animal-infecting counterparts, plant bunyaviruses use capped RNA leaders cleaved from host cellular mRNAs to prime viral genome transcription in a process called cap-snatching, but in vivo systems to investigate the details of this process are lacking for them. Here, we report that Rice stripe tenuivirus (RSV) and Tomato spotted wilt tospovirus (TSWV) cleave capped RNA leaders from mRNAs transiently expressed by agroinfiltration, which makes it possible to artificially deliver defined cap donors to the two plant bunyaviruses with unprecedented convenience. With this system, some ideas regarding how plant bunyaviruses select and use capped RNA leaders can be tested easily. We were also able to obtain clear evidence that the capped RNA leaders selected by TSWV are generally longer than those by RSV. TSWV frequently uses the prime-and-realign mechanism in transcription primed by capped RNA leaders shorter than a certain length, like that has been demonstrated recently for RSV.

4.
J Colloid Interface Sci ; 559: 282-290, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31634672

RESUMO

The improvement of electrocatalysts in hydrogen evolution reaction (HER) activity can be achieved by two strategies: (i) to enhance the intrinsic catalytic activity, and (ii) to improve the active-site exposure. In this work, nickel sulfide (Ni3S2), as an efficient pre-electrocatalyst, is developed by a facile, mild and in-situ electrochemical (EC) pretreatment for enhancement in HER activity. It is found that after the EC treatment, the required overpotential for HER greatly decreases from 288 mV (pristine-Ni3S2) to 169 mV (EC-Ni3S2) at 10 mA cm-2 in 1.0 M KOH, and is stable for over 25 h with nearly unchanged structure and chemical composition. Two possible mechanisms are suggested to explain this enhancement: (i) the oxygen-doped sulfur-deficient Ni3S2 (Ni3S2-xOx) layer should have been formed on the surface of Ni3S2 nanosheets, which brings about the electronic environment modulation, resulting in the optimized hydrogen (H*) adsorption/desorption and higher electrical conductivity; (ii) the developed nanosheets/microspheres structure with poor crystallinity increases the number of active sites in hydrogen generation. The promotion in HER performance of Ni3S2 electrocatalyst via EC pretreatment may exploit the potential for nickel sulfide and other transition metal dichalcogenide (TMD) electrocatalysts to achieve high efficiency and stability for electrochemical energy conversion and storage.

5.
Gene ; 725: 144143, 2020 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-31629816

RESUMO

Atherosclerosis is a common cardiovascular disorder and is characterized by damage of endothelial cells, cell inflammation, hyper-proliferation of vascular smooth muscle cells and the accumulation of extracellular lipids and fibrous tissues. In this study, we firstly examined the expression level of long intergenic non-protein coding RNA, regulator of reprogramming (linc-ROR) in homocysteine (Hcy)-stimulated human aortic smooth muscle cells (HASMCs), and then looked into the potential molecular signaling axis of linc-ROR in regulating the proliferation and migration of HASMCs. Hcy promoted HASMC proliferation and up-regulated linc-ROR expression. Functional studies showed that linc-ROR exerted enhanced actions on the proliferation and migration of HASMCs. In addition, linc-ROR acted as a competing endogenous RNA for miR-195-5p and repressed the miR-195-5p expression in HASMCs. Linc-ROR was up-regulated the miR-195-3p was down-regulated in the plasma from CAD patients when compared to normal controls. Furthermore, fibroblast growth factor 2 (FGF2) was identified as a target of miR-195-5p and was negatively regulated by miR-195-5p in HASMCs. The rescue experiments revealed that linc-ROR-mediated HASMC proliferation and migration may be via regulating miR-195-5p/FGF2 axis. Linc-ROR inhibition blocked the miR-195-5p/FGF2 signaling in Hcy-treated HASMCs, and this effect may also involve in the miR-195-5p/FGF2 axis. To summarize, the data of the present study identified the up-regulation of linc-ROR in Hcy-stimulated HASMCs, and further mechanistic functional studies revealed that linc-ROR promoted HASMC proliferation and migration via regulating miR-195-5p/FGF2 axis. The present study provided the novel actions of linc-ROR in regulating HASMC proliferation and migration, which may be related to the pathophysiology of atherosclerosis.

6.
Nanotechnology ; 31(5): 05LT01, 2020 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-31100734

RESUMO

Deformable microfluidics may be potentially used in cell manipulation, optical sensing, and imaging applications, and have drawn considerable scientific interests in the recent past. The excellent tunability of deformable microfluidic devices can provide controllable capture, deposition, and target release. We demonstrated a one-dimensional nano-sieve device to capture microparticles from suspensions. Size-selective capturing and release of micro- and nanoparticles was achieved by simply adjusting the flow rate. Almost all the microparticles were trapped in the nano-sieve device at a flow rate of 20 µl min-1. Increasing the flow rate induces a hydrodynamic deformation of the roof of the compliant device and allows most of the microparticles to pass through the channel. We also established a theoretical model based on computational fluid dynamics to reveal the relationship of the hydrodynamically induced deformation, channel dimensions, and capture efficiency that supports and rationalizes the experimental data. We have predicted the capture efficiency of micro-and nanoparticles in a nano-sieve device with various geometries and flow rates. This study may be important to the optimization of next generation deformable microfluidics for efficient micro- and nanostructure manipulations.

7.
Microvasc Res ; 127: 103913, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31449822

RESUMO

The "metabolic memory", a phenomenon that the target cell remembers the early hyperglycemia, has been reported to be a critical issue in diabetes pathogenesis. Here, we confirmed the inducible effects of high glucose (HG) and HG followed by normal glucose (HN) upon the proliferation and the tube formation capacity of human umbilical vein endothelial cells (HUVECs), as well as the suppressive effects of HG and HN on HUVEC apoptosis. In the meantime, the miR-320 expression could be dramatically downregulated (** and ## P < 0.01), whereas VEGFA expression (** and ## P < 0.01) and VEGFA, PKC, and RAGE protein levels could be remarkably induced via HG and HN stimulation. More importantly, the effects of HG and HN were not significantly different, suggesting the existence of high glucose-induced metabolic memory and the involvement of miR-320 and VEGFA in high glucose-induced metabolic memory in HUVECs. Consistently, miR-320 overexpression significantly reversed the effects of HG and HN on HUVECs (* and # P < 0.05, ** and ## P < 0.01). miR-320 suppressed the expression of VEGFA via direct binding to the 3'-UTR of VEGFA mRNA, therefore suppressing high glucose-induced metabolic memory (** P < 0.01); the effects of miR-320 overexpression on HUVECs could be reversed by VEGFA overexpression (# P < 0.05, ## P < 0.01), indicating that miR-320/VEGFA axis modulates the proliferation, apoptosis, and the angiogenesis capacity of HUVECs. In conclusion, we demonstrate that miR-320/VEGFA axis is crucial to high glucose-induced metabolic memory during HUVEC dysfunction and may be involved in the pathology of diabetes.

8.
9.
Chemosphere ; 240: 124900, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31563099

RESUMO

Spirotetramat (SPT) is a new tetronic acid derivative insecticide used to control scales and aphids; the potential for endocrine disruptor effects in fish could not be finalized with the available data. In this study, zebrafish were selected to assess the endocrine-disrupting effects. Significant decrease of plasma estradiol (E2), testosterone (T) and 11-ketotestosterone (11-KT) were observed in both male and female following the spirotetramat exposure; the vitellogenin (VTG) level in females significantly decreased. The expression of the hypothalamic-pituitary-gonad (HPG) axis genes fshr, lhr and esr1 showed significant increase in the gonads, which expression in males is higher than in females. In addition, the activities of capspase-3 and caspase-9 significantly decreased in both males and females liver, while the capspase-3 and caspase-9 were increased in male testis, the mRNA expression levels of genes expression related to the apoptosis pathway were also significantly altered after the spirotetramat exposure. Additionally, we found the parental zebrafish exposed to spirotetramat induced the development delay of its offspring. Above all, the adverse effects induced by spirotetramat suggesting that spirotetramat is a potential exogenous hazardous agent.

10.
J Affect Disord ; 260: 105-110, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31494361

RESUMO

BACKGROUND: Previous research on the relationship between life satisfaction and its influencing factors has mainly focused on the work domain. Psychological strains, which result from these stress-related outcomes, have not been paid enough attention to explain how it correlates negatively with life satisfaction. METHOD: A cross-sectional study was conducted, using questionnaires sent to selected medical staff in a public hospital in Shandong, China (N = 1012). Multiple regression analysis was used to investigate how psychological strains influencing life satisfactions among medical staff. RESULTS: The findings indicate that aspiration strain and deprivation strain have significantly negative impact on medical staff's life satisfaction even with other variables controlled for. Weekly working hour was a significant predictor for life satisfaction. Family factors, such as marital status and kids in the family as well as social support were important factors in influencing individuals' life satisfaction. CONCLUSION: The current study highlights the negative associations between aspiration strain, deprivation strain and life satisfaction. The result underlines the importance of actions taken to prevent and combat psychological strains. It also provides some evidence for policy makers to improve the work environment for medical staff, such as reduce weekly working hours and enhance social support in order to increase medical staff's life satisfaction.

11.
Artigo em Inglês | MEDLINE | ID: mdl-31674637

RESUMO

Temporoinsular gliomas are frequently large-sized tumors that require meticulous planning to ensure maximum surgical resection and minimal neurologic deficits in patients. Here, we demonstrate our technique encompassing multi-modal imaging guidance and awake brain mapping which enables maximum safe resection of such tumors. The patient, a 39-yr-old man, presented with depression and memory loss for 18 mo. Preoperative magnetic resonance imaging (MRI; MAGNETOM Verio, Siemens) revealed a nonenhancing lesion in the left dominant temporoinsular lobe. Three-dimensional magnetic resonance spectroscopy was used to analyze the choline/N-acetyl-aspartate index which suggested a low-grade glioma diagnosis. Informed patient consent was obtained. After craniotomy, the mouth motor, speech arrest, and word generation areas were mapped via direct cortical stimulation under awake mapping. A strip electrode was placed across the precentral gyrus for continuous motor evoked potential monitoring. Cortical incisions were made in nonfunctional cortical areas and tumor was resected in the temporal lobe. Following this, tumor at the inferior insular zone was carefully debunked with Cavitron Ultrasonic Surgical Aspirator (Integra Lifescience) also through the temporal window. The hippocampus was preserved since it was not invaded by tumor. Subcortical mapping combined with Diffuse Tensor Imaging tractography-based navigation (Medtronic lnc.) was performed to localize the motor and language pathways. Intraoperative MRI evaluation showed tumor resection extent of 95%. Pathological and molecular analysis revealed a diagnosis of Grade II IDH-mutant oligodendroglioma. After surgery the patient was administered chemotherapy (Temozolomide). He recovered without language or motor deficits.

12.
Insect Biochem Mol Biol ; 116: 103264, 2019 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-31707207

RESUMO

Elaborate regulation of tissue- and stage-specific expression of genes is prerequisite for insect development. The hormone 20-hydroxyecdysone (20E) initiates metamorphosis by regulating the expression of a series of genes. However, how 20E orderly regulates the pupa-specific expression of genes remains unclear. In this study, we report a regulatory mechanism for the pupa-specific expression of chitin synthase A 2b (CHSA-2b) in Bombyx mori. We found that Broad-Complex Z4 (BR-C Z4) was up-regulated by 20E just before pupation, while transcription factor FoxJ and CHSA-2b were up-regulated during the pupal stage. There is a Fox cis-regulatory element in the CHSA-2b promoter region, and FoxJ protein bound to this element, enhancing the CHSA-2b transcription during the pupal stage. In addition to CHSA-2b, FoxJ also up-regulated the expression of 16 out of 19 pupa-specific genes tested. However, at the prepupal stage, 20E-induced BR-C Z4 inhibited the FoxJ transcription, indirectly inhibiting the CHSA-2b transcription. These data suggest that at the pre-pupation stage, 20E-induced BR-C Z4 inhibited the expression of pupa-stage genes like CHSA-2b by inhibiting the expression of FoxJ; by the pupal stage, the expression of BR-C Z4 decreased, releasing its inhibition on FoxJ, which then up-regulated the expression of the pupa-specific genes. This study explains the elaborate regulation of the pupa-specific gene expression during metamorphosis in B. mori.

13.
Brain Res Bull ; 154: 91-101, 2019 Nov 11.
Artigo em Inglês | MEDLINE | ID: mdl-31726090

RESUMO

Fibroblast growth factor 9 (FGF9) is a member of the fibroblast growth factor family and is widely expressed in the central nervous system (CNS). However, it is not clear how the working mechanism of FGF9 is involved in cerebellar development. To address this question, we deleted the Fgf9 gene specifically in GABAergic neurons or glutamatergic neurons, and demonstrated that Fgf9 ablation in GABAergic neurons rather than the glutamatergic neurons caused severe ataxia. We showed that FGF9 played a key role in the survival and development of Purkinje cells. GABAergic neuron-specific knockout of FGF9 (Fgf9VGAT) significantly affected the survival and development of Purkinje cells, disrupting Bergmann fiber scaffold formation and granule neuron migration in mice. RNA sequencing revealed that 976 differentially expressed genes (DEGs) were identified between Fgf9VGAT and control mice. The DEGs with significantly upregulated expression were found to be involved in apoptotic and inflammatory signaling. Selected genes including Fas, Bid, Mapk11, Cxcl10, CCl2, Bik and Fos, were validated by qRT-PCR and exhibited increases in expression in Fgf9VGAT mice compared to control mice similar to those seen in the RNA-sequencing data. The expression levels of apoptosis- and inflammation-related proteins were also increased, especially those of Fas and caspase-3 pathway related proteins. Interestingly, activated ERK signaling has been observed in apoptosis and inflammatory responses induced by deleting Fgf9 in GABAergic neurons.

14.
Environ Int ; 134: 105313, 2019 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-31731000

RESUMO

Exposure to environmental pollutant organochlorine pesticides (OCPs) and the role of tumour suppressor GSTs gene polymorphisms as well as epigenetic alterations have all been well reported in hepatocarcinogenesis. However, the interplay between environmental risk factors and polymorphic tumour suppressor genes or epigenetic factors in hepatocellular carcinoma (HCC) development remains ambiguous. Herein, we investigated the relationship of three GSTs polymorphisms (GSTT1 deletion, GSTM1 deletion, GSTP1 rs1695) as well as GSTP1 promoter region DNA methylation and HCC risk with a particular focus on the interaction with OCPs exposure among 90 HCC cases and 99 controls in a Chinese population. Serum samples were analysed for OCPs exposure employing gas chromatography coupled with mass selective detector (GC-MS). GSTs polymorphisms and epigenetic alterations were determined using high-resolution melting PCR (HRM PCR) and DNA sequencing. After adjusting for confounders (HBV infection, smoking, alcohol consumption, BMI, age, gender), OCPs exposure and GSTP1 methylation is significantly associated with elevated risk of HCC, while no significance is observed for GSTs polymorphisms. Moreover, the effects of OCPs exposure on HCC risk are more pronounced amongst GSTP1 (Ile/Val + Val/Val) and GSTP1 promoter methylation subjects than those who were GSTP1 (Ile/Ile) and unmethylated subjects. The interactions between OCPs exposure and GSTP1 genotype as well as GSTP1 epigenetic status are statistically significant. The current study demonstrates the importance of gene-environment interactions in the multifactorial development of HCC.

15.
Nanoscale ; 11(46): 22539-22549, 2019 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-31746897

RESUMO

Dielectric composites constructed using carbon and metal oxides have become a hot research topic; however, the strategy to strengthen the coupling of components still needs to be optimized to enhance dielectric loss. Herein, ultra-fine ZnO derived from ZIF-8 was uniformly distributed and tightly embedded in multi-wall carbon nanotubes (C-ZnO@CNTs) via a novel confined space synthesis. Due to the presence of a polypyrrole coating, ZnO nanocrystals could be formed in the space of the original polyhedron and inserted into the CNTs, promoting the generation of polarized CNTs and providing abundant polarization centers on the CNTs. The composites exhibited superior microwave absorption capacity with a reflection loss value of up to -48.2 dB at 6.0 GHz, and the effective bandwidth reached 14.9 GHz by adjusting their thickness. According to the geometric phase analysis, the strain driven by the tight-coupling between ZnO-CNTs was confirmed to exist in the interfaces, boosting their inherent electromagnetic properties. The improved dielectric loss was caused by the strong interfacial polarization among ZnO-ZnO or ZnO-CNTs and the conductive loss among intertwined CNTs network, as revealed by electron holography. Therefore, the overall electrical properties could be improved by the polarized C-ZnO@CNTs with high electron conductivity. The confined space strategy may have promising potential for the synthesis of new composites of polarized carbon materials tightly coupled with metal oxides nanocrystals.

16.
Artigo em Inglês | MEDLINE | ID: mdl-31771326

RESUMO

Photodynamic therapy (PDT) takes advantage of reactive oxygen species (ROS) to trigger the apoptosis for cancer therapy. Given cell apoptosis is a form of programmed cell death involved with multiple sub-organelles and cancer cells are more sensitive to ROS than normal cells, early confirmation of the apoptosis induced by ROS would effectively avoid overtreatment. Herein, we highlight an aggregation-induced emission (AIE) based theranostic agent (TPA3) to in-situ dynamically track mitophagy prior to late apoptosis. TPA3 showed high specificity to autophagy vacuoles (AVs), of which appearance is the signature event of mitophagy during early apoptosis, and delivered photocytotoxicity to cancer cells and skin cancer tumors in nude mice under irradiation of white light. Fur-thermore, in-situ monitoring of dynamical mitophagy process involved with mitochondria, AVs, and lysosomes was performed for the first time under confocal microscopy, providing a real-time self-monitoring system for assessing the curative effect prior to late apop-tosis. This fluorescence imaging guided PDT witness great advances for applying in the clinical application.

17.
J Diabetes Complications ; : 107464, 2019 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-31771933

RESUMO

AIMS: Our aim was to search for clinical predictors of good glycemic control in patients starting or intensifying oral hypoglycemic pharmacological therapy. METHODS: A multicenter, prospective cohort of 499 diabetic subjects was enrolled in this study: patients with newly diagnosed diabetes (NDM group) or poor glycemic control with oral antidiabetic drugs (OADs) (PDM group). All subjects then started or intensified OADs therapy and followed up for 91 days. Glycemic control was determined according to HbA1c at day 91 with HbA1c <7% considered good. RESULTS: The proportions of patients with good glycemic control after follow up for 91 days were 66.9% and 34.8% in NDM group and PDM group respectively. Logistic regression analysis showed that the change in GA at 28 days was the only predictor of good glycemic control in NDM patients (OR = 1.630, 95% CI 1.300-2.044, P < 0.001). In PDM patients, changes in GA at 28 days, CPI, baseline HbA1c, diabetic duration, and BMI were all independent predictors of good glycemic control (All P < 0.05). CONCLUSIONS: GA decline is a good predictor of future success in newly diagnosed patients. In patients intensifying therapy, beside GA decline, other individualized clinical characteristics should also be considered.

18.
Emerg Radiol ; 2019 Nov 26.
Artigo em Inglês | MEDLINE | ID: mdl-31773437

RESUMO

PURPOSE: Evaluate the potential effects of X-ray tube voltage (kV) changes on Hounsfield unit (HU) measurements of hemoperitoneum in patients with blunt splenic injuries. METHODS: Eight different tissue equivalent electron density plugs in the Electron Density Phantom were scanned (muscle, adipose, breast, liver, lung (exhale), lung (inhale), trabecular bone, and dense bone). The phantom was scanned at different kV values (70, 80, 100, 120, and 140 kV). In the clinical study, the local trauma registry database was queried for splenic injuries between January 2015 and December 2016 with a final cohort of 110 patients. The average HU numbers of hemoperitoneum found in three different anatomic locations (pelvic, perisplenic, and perihepatic) were compared at different kV values (100 kV, 120 kV, and 140 kV). ANOVA and pairwise t tests were performed for statistical analysis. RESULTS: In both studies, HU measurements generally decreased as kV increased, and vice versa. One hundred ten patients were reviewed: 29 for 100 kV, 66 for 120 kV, and 15 for 140 kV. For the perihepatic group, significant differences were observed in average HU in the following pairwise comparisons: 100/140 (13.7 (5.3), p < 0.05) and 120/140 (10.3 (4.5), p < 0.05). For the perisplenic group, significant differences were observed in 100/120 (7.0 (3.5), p < 0.05) and 100/140 (13.2 (4.9), p < 0.05). No significant difference was observed in the pelvic location (p = 0.5594). CONCLUSIONS: HU measurements of hemoperitoneum in patients with blunt splenic injuries significantly varied with the use of different kV values. Radiologists should be aware of the possible effects of altering kV on HU.

19.
Integr Zool ; 2019 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-31773891

RESUMO

Superior species may have distinct advantages over subordinates within asymmetrical interactions among sympatric animals. However, exactly how the subordinate species coexists with superior species is unknown. In the forests western Beijing city, intense asymmetrical interactions of food competition exist among granivorous rodents (e.g. Apodemus peninsulae, Niviventer confucianus, Sciurotamias davidianus, Tscherskia triton) that have broadly overlapping habitats and diets, but have varied body-size (range 15 - 300 g), hoarding habit (scatter vs. larder) and/or daily rhythm (diurnal vs. nocturnal). The smallest rodent, A. peninsulae, which usually faces high competitive pressure by larger rodents, is an ideal model to explore how subordinate species coexist with superior species. Under semi-natural enclosure conditions, we tested responses of seed-hoarding behaviour in A. peninsulae to intra- and inter-specific competitors at the situations of pre-competition (without competitor), competition (with competitor) and post-competition (competitor removed). The results showed that A. peninsulae increased intensity of larder-hoarding, reduced intensity of scatter-hoarding in the presence of intraspecifics and S. davidianus, whereas, they ceased foraging and hoarding in the presence of N. confucianus and T. triton. A. peninsulae reduced intensity of hoarding outside the nest, and moved more seeds into the nest for larder-hoarding under competition from intraspecific individuals and S. davidianus. In most cases, the experimental animals could recover to its original state of pre-competition when competitors were removed. These results suggest that subordinate species contextually regulate their food-hoarding strategies according to different competitors, promoting species coexistence among sympatric animals that have asymmetrical food competition. This article is protected by copyright. All rights reserved.

20.
Environ Sci Technol ; 2019 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-31774261

RESUMO

The exhaust gas contains harmful products, including fuel-additive elements such as compounds of sodium, which cause dramatic catalyst deactivation of catalysts during selective catalytic reduction (SCR) of NO with NH3. There is an increasing demand to synthesize alkali poisoning-resistant catalysts for industrial NH3-SCR applications. In the present study, the as-synthesized Fe2O3/MoO3/TiO2 exhibits a high degree of resistance toward Na2SO4 poisoning during the NH3-SCR reaction. With 500 µmol g-1 Na+ poisoning, the Fe2O3/MoO3/TiO2 showed approximately 95% (or more) of its original activity throughout the entire temperature rage. Even with 700 µmol g-1 Na+ poisoning, Fe2O3/MoO3/TiO2 still performed well. The 500 and 700 µmol Na+ g-1 loadings dictate that on average, SCR catalysts could be exposed to alkali-rich and highly dusty environments for over 14000 and 20000 hours, respectively. The layered MoO3 building block is used as a binding buffer and sandwiched between the active phase and TiO2 support to provide sufficiently stable binding sites for Na2SO4 poison and to present alkali blocking of the surface active phase. Our findings provide useful information regarding the use MoO3 as a safety buffer for developing functional NH3-SCR catalysts with enhanced alkali-poisoning resistant performance and long lifetimes.

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