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1.
Huan Jing Ke Xue ; 41(6): 2536-2546, 2020 Jun 08.
Artigo em Chinês | MEDLINE | ID: mdl-32608767

RESUMO

Secondary species are dominant components of PM2.5 in Dushanzi, Xinjiang. It is crucial to investigate the conversion process of secondary components in the atmosphere for regional air pollution control. The water-soluble components were analyzed for samples collected from Dushanzi District of Xinjiang from September 2015 to July 2016. The results showed that the total water-soluble ions (TWSIs) showed a seasonal variation consistent with PM2.5, and the seasonal variation of the ions was in the order-winter (67.86 µg·m-3) > autumn (13.77 µg·m-3) > spring (10.09 µg·m-3) > summer (4.85 µg·m-3); secondary ions (NH4+, SO42-, and NO3-)-accounting for 98% of TWSIs in winter. The results of the aerosol thermodynamic model (E-AIM) that explores the particle liquid water and acidity in Dushanzi District showed that the particles in Dushanzi are acidic with an annual in-situ pH of 0.81, and the pH value of the winter samples was the highest (2.93). The seasonal variation of particles in water was of the order: winter (331.32 µg·m-3) > autumn (5.91 µg·m-3) > spring (5.46 µg·m-3) > summer (1.62 µg·m-3). The annual average nitrogen oxidation rate and sulfur oxidation rate were 0.13 and 0.47, respectively, indicating a secondary conversion of regional pollutants. Further analysis showed that the concentration of sulfate in the particle phase was significantly affected by liquid water content of particles and in-situ pH. The formation of nitrate was mainly caused by heterogeneous reactions under high water content of particle.

2.
Environ Sci Technol ; 2020 Jun 29.
Artigo em Inglês | MEDLINE | ID: mdl-32598136

RESUMO

The polycyclic aromatic hydrocarbons (PAHs) as constituents of urban grime and indoor surfaces can impact the photochemical conversion of nitrogen dioxide (NO2) to nitrous acid (HONO) thereby impacting the oxidation capacity of the atmosphere. In this study we investigate the effect of relative humidity (RH %), light intensity and NO2 concentrations on uptake coefficients (γ) of NO2 on solid film consisted of fluorene (FL) and a mixture of FL and Na2SO4 as proxy for urban and indoor grime at ambient pressure and temperature. The γ(NO2) on solid FL increased markedly from (5.7 ±1.7) · 10-7 at 0 % RH to (4.6 ± 1.0) · 10-6 at 90 % RH. The NO2 to HONO conversion yield, (∆HONO/∆NO2)%, increase with RH from 40 % at 0% RH up to 80 % at 60 to 90 % RH, indicating that the water molecules favor the formation of HONO up to 60 % RH. These results suggest that the heterogeneous photochemical reaction of NO2 on FL and FL/Na2SO4 can be an important source of HONO in the urban environment and indoor atmosphere and should be considered in photochemical models.

3.
Cell Res ; 2020 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-32561861

RESUMO

Common fragile sites (CFSs) are genomic loci prone to the formation of breaks or gaps on metaphase chromosomes. They are hotspots for chromosome rearrangements and structural variations, which have been extensively implicated in carcinogenesis, aging, and other pathological processes. Although many CFSs were identified decades ago, a consensus is still lacking for why they are particularly unstable and sensitive to replication perturbations. This is in part due to the lack of high-resolution mapping data for the vast majority of the CFSs, which has hindered mechanistic interrogations. Here, we seek to map human CFSs with high resolution on a genome-wide scale by sequencing the sites of mitotic DNA synthesis (MiDASeq) that are specific for CFSs. We generated a nucleotide-resolution atlas of MiDAS sites (MDSs) that covered most of the known CFSs, and comprehensively analyzed their sequence characteristics and genomic features. Our data on MDSs tallied well with long-standing hypotheses to explain CFS fragility while highlighting the contributions of late replication timing and large transcription units. Notably, the MDSs also encompassed most of the recurrent double-strand break clusters previously identified in mouse neural stem/progenitor cells, thus bridging evolutionarily conserved break points across species. Moreover, MiDAseq provides an important resource that can stimulate future research on CFSs to further unravel the mechanisms and biological relevance underlying these labile genomic regions.

4.
Small ; : e2001626, 2020 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-32548898

RESUMO

The development of a negative electrode for supercapacitors is a critical challenge for the next-generation of energy-storage devices. Herein, two new electrodes formed by the coordination polymers [Ni(itmb)4 (HPMo12 O40 )]·2H2 O (1) and [Zn(itmb)3 (H2 O)(HPMo12 O40 )]·4H2 O (2) (itmb = 1-(imidazo-1-ly)-4-(1,2,4-triazol-1-ylmethyl)benzene), synthesized by a simple hydrothermal method, are described. Compounds 1 and 2 show high capacitances of 477.9 and 890.2 F g-1 , respectively. An asymmetric supercapacitor device assembled using 2 which has novel water-assisted proton channels as negative electrode and active carbon as positive electrode shows ultrahigh energy density and power density of 23.4 W h kg-1 and 3864.4 W kg-1 , respectively. Moreover, the ability to feed a red light emitting diode (LED) also demonstrates the feasibility for practical use. The results allow a better elucidation of the storage mechanism in polyoxometalate-based coordination polymers and provide a promising direction for exploring novel negative materials for new-generation high-performance supercapacitors.

5.
Environ Sci Technol ; 2020 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-32479720

RESUMO

Formic acid (HCOOH), one of the most important and ubiquitous organic acids in the Earth's atmosphere, contributes substantially to atmospheric acidity and affects pH-dependent reactions in the aqueous phase. However, based on the current mechanistic understanding, even the most advanced chemical models significantly underestimate the HCOOH concentrations when compared to ambient observations at both ground-level and high altitude, thus underrating its atmospheric impact. Here we reveal new chemical pathways to HCOOH formation from reactions of both O3 and OH with ketene-enols, which are important and to date undiscovered intermediates produced in the photo-oxidation of aromatics and furans. We highlight that the estimated yields of HCOOH from ketene-enol oxidation are up to 60% in polluted urban areas and greater than 30% even in the continental background. Our theoretical calculations are further supported by a chamber experiment evaluation. Considering that aromatic compounds are highly reactive and contribute ca. 10% to global nonmethane hydrocarbon emissions and 20% in urban areas, the new oxidation pathways presented here should help to narrow the budget gap of HCOOH and other small organic acids and can be relevant in any environment with high aromatic emissions, including urban areas and biomass burning plumes.

6.
Acta Biomater ; 2020 Jun 23.
Artigo em Inglês | MEDLINE | ID: mdl-32590172

RESUMO

The transient period of regeneration potential in the postnatal heart suggests molecular changes with maturation influence the cardiac response to damage. We have previously demonstrated that injury and exercise can stimulate cardiomyocyte proliferation in the adult heart suggesting a sensitivity to exogenous signals. Here, we consider whether exogenous fetal ECM and mechanically unloading interstitial matrix can drive regeneration after myocardial infarction (MI) surgery in low-regenerative hearts of day5 mice. Compared to controls, exogenous fetal ECM increases cardiac function and lowers fibrosis at 3 weeks post-injury and this effect can be augmented by softening heart tissue. In vitro experiments support a mechano-sensitivity to exogenous ECM signaling. We tested potential mechanisms and observed that fetal ECM increases nuclear YAP localization which could be enhanced by pharmacological stabilization of the cytoskeleton. Blocking YAP expression lowered fetal ECM effects though not completely. Lastly we observed mechanically unloading heart interstitial matrix increased agrin expression, an extracellular node in the YAP signaling pathway. Collectively, these data support a combined effect of exogenous factors and mechanical activity in altering agrin expression, cytoskeletal remodeling, and YAP signaling in driving cardiomyocyte cell cycle activity and regeneration in postnatal non-regenerative mice. STATEMENT OF SIGNIFICANCE: With the purpose of developing regenerative strategies, we investigate the influence of the local niche on the cardiac injury response. We conclude tissue stiffness, as anticipated in aging or disease, impairs regenerative therapeutics. Most novel, mechanical unloading facilitates enhanced cardiac regeneration only after cells are pushed into a permissive state by fetal biomolecules. Specifically, mechanical unloading appears to increase extracellular agrin expression that amplifies fetal-stimulation of nuclear YAP signaling which correlates with observed increases of cell cycle activity in cardiomyocytes. The results further suggest the cytoskeleton is critical to this interaction between mechanical unloading and independently actived YAP signaling. Using animal models, tissue explants, and cells, this work indicates that local mechanical stimuli can augment proliferating-permissive cardiomyocytes in the natural cardiac niche.

7.
Nature ; 2020 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-32380511

RESUMO

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the cause of coronavirus disease 2019 (COVID-19), which has become a public health emergency of international concern1. Angiotensin-converting enzyme 2 (ACE2) is the cell-entry receptor for severe acute respiratory syndrome coronavirus (SARS-CoV)2. Here we infected transgenic mice that express human ACE2 (hereafter, hACE2 mice) with SARS-CoV-2 and studied the pathogenicity of the virus. We observed weight loss as well as virus replication in the lungs of hACE2 mice infected with SARS-CoV-2. The typical histopathology was interstitial pneumonia with infiltration of considerable numbers of macrophages and lymphocytes into the alveolar interstitium, and the accumulation of macrophages in alveolar cavities. We observed viral antigens in bronchial epithelial cells, macrophages and alveolar epithelia. These phenomena were not found in wild-type mice infected with SARS-CoV-2. Notably, we have confirmed the pathogenicity of SARS-CoV-2 in hACE2 mice. This mouse model of SARS-CoV-2 infection will be valuable for evaluating antiviral therapeutic agents and vaccines, as well as understanding the pathogenesis of COVID-19.

8.
ChemSusChem ; 2020 May 26.
Artigo em Inglês | MEDLINE | ID: mdl-32458562

RESUMO

Polymeric carbon nitrides (CNs) have been identified as attractive photocatalysts owing to their comparatively low cost and facile modification of their electronic structure. Herein, we report an effective strategy to tune the surface oxygen species linking site of polymeric CN, achieving more effective charge separation. A high photocatalytic hydrogen production rate of approximately 10225 µmol h-1 ⋅g-1 under visible light irradiation (λ>420 nm) and an impressive apparent quantum efficiency (AQE) of 5.7 % at 430 nm were recorded. Specifically, thermal treatment under a H2 and then an air atmosphere allowed the oxygen species linker on the surface of CN to be changed from -C=O to N=C-OH and then -C-O-C-, resulting in unbalanced charge distribution, which significantly enhanced the photogenerated charge separation, further contributing to the high hydrogen production performance. This linker regulation strategy may provide a new path for the development of highly efficient photocatalysts.

9.
Mediators Inflamm ; 2020: 1583647, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32351318

RESUMO

The ontogeny of macrophages in most organs has already been established. Owing to the limited number and inaccessibility of synovial macrophages (SMs), the origin of SMs has not been fully elucidated. Previous studies suggested that SMs have two major origins, namely, tissue-resident and monocyte-derived SMs. However, no systematic analysis to identify SM ontology in either physiological or pathological conditions has been available to date. In this review, we summarize relevant studies on the two main origins of SMs in rheumatoid arthritis (RA) and forecast the future research directions for this field. Furthermore, we discuss the current state of RA therapy that is based on targeting different SM subsets.

10.
Sci Total Environ ; 723: 138171, 2020 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-32392684

RESUMO

Volatile organic compounds (VOCs) play a crucial role in modulating air pollution by ozone and fine particles, particularly in urban areas. While in recent years short-term intervention actions for better air quality during big events in China did present good opportunities to examine the effectiveness of control measures in reducing anthropogenic VOCs emission, it is highly challenging to interpret the real effect of a specific control measure based on field monitoring data when a cocktail of control measures were adopted. Here we took the air quality intervention actions during the 16th Asian Games (AG) in Guangzhou as a case study to explore the impact of short-term multiple measures on VOCs reduction. The average mass concentrations of VOCs decreased by 52-68% during the AG. These percentages could not reflect emission reduction rates as the concentration might be also heavily impacted by dispersion conditions. Diagnostic ratios, such as methyl tert-butyl ether to carbon monoxide (MTBE/CO) and i-pentane/CO, decreased by over 60% during the AG, suggesting a substantial reduction in gasoline related emissions. A method linking emission reduction rates of two sources with their contribution percentages before and during the AG by using a receptor model was further formulated. With the available reduction rate of 34% for vehicular exhaust obtained during the traffic restriction drill in our previous study, VOCs emissions from gasoline evaporation and solvent use reduced by 45.7% and 13.6% during the AG, respectively. Total VOCs emissions decreased by 25.3% on average during the AG, and the emission control of vehicular exhaust, oil evaporation, and solvent use accounted for 17.0%, 6.3% and 2.0% of total VOCs emission reduction, respectively. This study presented an observed-based method with diagnostic/quantitative approaches to single out the effectiveness of each control measures in reducing VOCs emissions.

11.
Chem Asian J ; 15(11): 1750-1755, 2020 Jun 02.
Artigo em Inglês | MEDLINE | ID: mdl-32307903

RESUMO

A three-dimensional (3D) hollow CoWO4 composite grown on Ni-foam (3D-H CoWO4 /NF) based on a flower-like metal-organic framework (MOF) is designed by utilizing a facile dipping and hydrothermal approach. The 3D-H CoWO4 /NF not only possesses large specific areas and rich active sites, but also accommodates volume expansion/contraction during charge/discharge processes. In addition, the unique structure facilitates fast electron/ion transport of 3D-H CoWO4 /NF. Meanwhile, a series of characterization measurements demonstrate the appropriate morphology and excellent electrochemical performance of the material. The 3D-H CoWO4 /NF possesses a high specific capacitance of 1395 F g-1 , an excellent cycle stability with 89% retention after 3000 cycles and superior rate property. Furthermore, the 3D-H CoWO4 /NF can be used as a cathode to configurate an asymmetric supercapacitor (ASC), and 3D-H CoWO4 /NF//AC shows a good energy density (29.0 W h kg-1 ). This work provides a facile method for the preparation of 3D-hollow electrode materials with high electrochemical capability for advanced energy storage devices.

12.
Environ Pollut ; 263(Pt B): 114507, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32283398

RESUMO

The accurate derivation of the proportion and absorption enhancement of black carbon (BC)-containing aerosols in the atmosphere is critical to assess their effect on air quality and climate. Here, using the field measured size-resolved volatility shrink factor, BC bulk mass concentration and the BC mass fraction in BC-containing particles in winter Beijing, we retrieved and quantified both the number and mass concentration of (1) non-BC, (2) internally mixed BC and (3) externally mixed BC of ambient fine aerosol particles. The reliability of the retrieval method has been evaluated by comparing with the simultaneously measured data. The number fraction of BC-containing particles accounts for 60-78% of ambient fine particles, with internally (both BC core and coating materials) and externally mixed BC of 51-64% and 9-23%, respectively. Only for nucleated particles on clean days, when nucleation is a major source of aerosol particles, did the non-BC component dominate (54%). A large amount of aerosols are BC-containing particles, with mass fraction of 32-52%, suggesting the dominant role of BC in elevating mass concentration of particulate matter (PM) in a polluted urban area. We also show that the BC particles are thickly coated with coating thickness (characterized by Dp/Dc, ratio of the BC diameter before and after heating at 300 °C) of 1.6-2.2, implying efficient aging of BC particles in polluted urban area. Our results imply a large proportion of BC-containing particles in the atmosphere, which could help towards understanding the role of BC on regional haze formation and climate forcing.

13.
Influenza Other Respir Viruses ; 14(4): 452-459, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32267084

RESUMO

BACKGROUND: Pediatric pneumonia remains a significant health challenge, while the viral risk factors for adverse outcomes in pediatric pneumonia are not yet fully clear. METHODS: A matched case-control study of pediatric patients with pneumonia was carried out in Beijing, China, between 2007 and 2015. The study enrolled 334 intensive care unit patients who developed life-threatening diseases and 522 controls matched to the sex, age, ethnicity, admission dates, and residing district of the cases suffered from pneumonia. Nasopharyngeal aspirates were taken from all participants and tested by PCR for 18 common respiratory viruses. RESULTS: At least, one virus was detected in 257 (77%) of the cases and 409 (78%) of the controls. We observed no difference in the prevalence of 17 respiratory viruses between cases and controls but found a higher frequency of influenza A virus (IFV-A) in the cases than in the controls (7% vs 4%, P = .036). After adjusting for comorbid conditions and a history of reactive airway diseases, IFV-A was associated with an increase in life-threatening pneumonia (adjusted odds ratio = 2.55, 95% CI = 1.24-5.24). Young age and congenital heart disease (aOR = 10.16-10.27, P < .001) were also independent risk factors. CONCLUSIONS: The prevention of IFV infection is critical in decreasing the risk of life-threatening pneumonia in children.

14.
Sci Total Environ ; 724: 138179, 2020 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-32272403

RESUMO

In this work, we analyzed freshly emitted particles from ship exhaust in the Guangzhou port region before and after the implementation of a clean fuel policy. We used a single particle aerosol mass spectrometer (SPAMS) to measure the changes in the chemical compositions of single particles and evaluate the role of V as a tracer for ship emissions. Particles from high sulfur fuel (SF) oil (HS) combustion ships consisted of 54.8% elemental carbon-vanadium-sulfate (EC-V-S) and 25.0% vanadium-sulfate (V-S) particles, while particles from low SF oil (LS) combustion ships were composed of 38.7% organic carbon-sulfate (OC-S) and 28.6% elemental and organic carbon (ECOC) particles. The sulfate-containing particles exhibited a moderate decrease from 95% in HS emissions to 78% in LS emissions, which still suggests the dominant role of sulfate in LS emissions after the implementation of a clean fuel policy. The V-containing particles showed a sharp decrease from 67% in HS emissions to 14% in LS emissions along with the decrease in the relative peak area (RPA) of V, suggesting a remarkable reduction in V in ship exhaust. The count of V-containing particles in urban Guangzhou in June 2017 was generally ten times lower than that in June 2016, which was in accordance with the sharp decrease in V-containing particles in LS emissions rather than in HS emissions. Despite the decrease in V in source-oriented ship emitted particles, the ubiquitous distribution of V in particles from lower SF combustion ships suggests V is still effective as a tracer of ship emissions in port regions after the implementation of the clean fuel policy. Furthermore, the particles from LS emissions were investigated in comparison to those from gasoline vehicles (GV), diesel vehicles (DV) and coal combustion (CC) sources to better resolve ship-related particles in port regions.

15.
Sci Total Environ ; 722: 137934, 2020 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-32208274

RESUMO

Driving conditions are among the important factors determining gasoline vehicle emissions, yet their relation with exhaust-derived secondary pollutants is poorly understood. Here, we introduced exhaust from a gasoline vehicle under hot idling and cruising conditions into an indoor smog chamber by using a chassis dynamometer and investigated the formation of secondary organic aerosols (SOA) during photochemical ageing under light after characterizing the primary emission of non-methane hydrocarbons (NMHCs), nitrogen oxide (NOx) and primary organic aerosol (POA) in the dark. When compared to emission factors (EFs) at idling, during cruising at 20 km h-1 or 40 km h-1, the EFs of NMHCs decreased by more than an order of magnitude, while the EFs of NOx were more than doubled, resulting in a large drop in the NMHC-to-NOx ratios. The percentages of reactive alkenes and aromatic hydrocarbons also decreased from idling to cruising at 20 km h-1 to that at 40 km h-1. The emission factor of benzene, a carcinogenic compound, decreased more than 10 times from ~0.35 g kg-fuel-1 at idling to ~0.03 g kg-fuel-1 during cruising. During photochemical ageing of exhaust, substantial SOA was formed, and the SOA/POA ratios decreased from 52 to 92 at idling to 4-14 during cruising. Traditional aromatics could explain 30-64% of the measured SOA at idling but less than 15% of the measured SOA during cruising. Our results highlight that traffic congestion would greatly promote the emission of reactive volatile organic compounds and carcinogenic benzene from gasoline vehicles and also show that NMHCs as a target in gasoline vehicle emission tests cannot effectively represent the SOA and ozone formation potentials of the partially oxidized hydrocarbons from poorly functioning converters.

16.
Proc Natl Acad Sci U S A ; 117(9): 5006-5015, 2020 03 03.
Artigo em Inglês | MEDLINE | ID: mdl-32071246

RESUMO

Multiple G protein-coupled receptors (GPCRs) are targets in the treatment of dementia, and the arrestins are common to their signaling. ß-Arrestin2 was significantly increased in brains of patients with frontotemporal lobar degeneration (FTLD-tau), a disease second to Alzheimer's as a cause of dementia. Genetic loss and overexpression experiments using genetically encoded reporters and defined mutant constructs in vitro, and in cell lines, primary neurons, and tau P301S mice crossed with ß-arrestin2-/- mice, show that ß-arrestin2 stabilizes pathogenic tau and promotes tau aggregation. Cell and mouse models of FTLD showed this to be maladaptive, fueling a positive feedback cycle of enhanced neuronal tau via non-GPCR mechanisms. Genetic ablation of ß-arrestin2 markedly ablates tau pathology and rescues synaptic plasticity defects in tau P301S transgenic mice. Atomic force microscopy and cellular studies revealed that oligomerized, but not monomeric, ß-arrestin2 increases tau by inhibiting self-interaction of the autophagy cargo receptor p62/SQSTM1, impeding p62 autophagy flux. Hence, reduction of oligomerized ß-arrestin2 with virus encoding ß-arrestin2 mutants acting as dominant-negatives markedly reduces tau-laden neurofibrillary tangles in FTLD mice in vivo. Reducing ß-arrestin2 oligomeric status represents a new strategy to alleviate tau pathology in FTLD and related tauopathies.


Assuntos
Demência Frontotemporal/patologia , beta-Arrestina 2/metabolismo , Proteínas tau/metabolismo , Doença de Alzheimer/metabolismo , Animais , Autofagia , Encéfalo/metabolismo , Encéfalo/patologia , Modelos Animais de Doenças , Demência Frontotemporal/metabolismo , Degeneração Lobar Frontotemporal/metabolismo , Camundongos , Camundongos Knockout , Camundongos Transgênicos , Neurônios/metabolismo , Neurônios/patologia , Transcriptoma , beta-Arrestina 2/genética
17.
Environ Sci Technol ; 54(6): 3114-3120, 2020 03 17.
Artigo em Inglês | MEDLINE | ID: mdl-32022545

RESUMO

Northern China is regularly subjected to intense wintertime "haze events", with high levels of fine particles that threaten millions of inhabitants. While sulfate is a known major component of these fine haze particles, its formation mechanism remains unclear especially under highly polluted conditions, with state-of-the-art air quality models unable to reproduce or predict field observations. These haze conditions are generally characterized by simultaneous high emissions of SO2 and photosensitizing materials. In this study, we find that the excited triplet states of photosensitizers could induce a direct photosensitized oxidation of hydrated SO2 and bisulfite into sulfate S(VI) through energy transfer, electron transfer, or hydrogen atom abstraction. This photosensitized pathway appears to be a new and ubiquitous chemical route for atmospheric sulfate production. Compared to other aqueous-phase sulfate formation pathways with ozone, hydrogen peroxide, nitrogen dioxide, or transition-metal ions, the results also show that this photosensitized oxidation of S(IV) could make an important contribution to aerosol sulfate formation in Asian countries, particularly in China.


Assuntos
Poluentes Atmosféricos , Transtornos de Fotossensibilidade , Aerossóis , Ásia , China , Humanos , Material Particulado , Sulfatos
18.
J Colloid Interface Sci ; 568: 130-138, 2020 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-32088443

RESUMO

Binary transition metal oxides as electroactive materials have continuously aroused grumous attention due to their high theoretical specific capacitance, high valtage window, and multiple oxidation states. However, the tiny specific surface area, poor conductivity and unsatisfactory cycle stability limit their practical application. Hence, a synthetic strategy is designed to fabricate a dual-tasking hollow cube nickel ferrite (NiFe2O4) - based composite (NiFe2O4-NiCo-LDH@rGO) with hierarchical structure. The composite is constructed by firstly preparing hollow NiFe2O4 from cube-like Ni - Fe bimetallic organic framework (NiFe-MOF), and then integrating nickel cobalt layered double hydroxide (NiCo-LDH) nanowires, together with reduced graphene oxide (rGO) via pyrolysis in conjuction with hydrothermal method. The NiFe2O4 possessing cubic hollow structure contributes to a huge accessible surface area, meanwhile alleviates large volume expansion/contraction effect, which facilitates suffcient permeation of the electrolyte and rapid ion/charge transport, and results in high cycling stability. The introduction of layered NiCo-LDH results in hierarchical structure and thus offers maximum contact areas with electrolyte, which heightens the specific capacitance of obtained composite and enhances the electro-catlytic activity towards oxidation of glucose. Furthermore, rGO layer greatly improves the electrical conductivity and ion diffusion/transport capability of composite. Benefiting from the unique structure and individual components of NiFe2O4-NiCo-LDH@rGO composite, the electrode delivers a high specific capacitance (750 C g-1) and superb durability. Simultaneously, the asymmetrical device based on NiFe2O4-NiCo-LDH@rGO as positive electrode delivers remarkable energy density (50 Wh kg-1). Moreover, NiFe2O4-NiCo-LDH@rGO exhibits good sensing performance with a sensitivity of 111.86 µA/µM cm-2, the wide linear range of 3.500 × 10-5 - 4.525 × 10-3 M, and the detection limit of 12.94 × 10-6 M with a signal to noise ratio of 3. Consequently, the NiFe2O4-NiCo-LDH@rGO could provide a prospective notion constructing bifunctional materials with hollow-cube hierarchical structure in the field of supercapacitors and electrochemical sensors.

19.
Chin Med J (Engl) ; 133(9): 1015-1024, 2020 May 05.
Artigo em Inglês | MEDLINE | ID: mdl-32004165

RESUMO

BACKGROUND: Human infections with zoonotic coronaviruses (CoVs), including severe acute respiratory syndrome (SARS)-CoV and Middle East respiratory syndrome (MERS)-CoV, have raised great public health concern globally. Here, we report a novel bat-origin CoV causing severe and fatal pneumonia in humans. METHODS: We collected clinical data and bronchoalveolar lavage (BAL) specimens from five patients with severe pneumonia from Wuhan Jinyintan Hospital, Hubei province, China. Nucleic acids of the BAL were extracted and subjected to next-generation sequencing. Virus isolation was carried out, and maximum-likelihood phylogenetic trees were constructed. RESULTS: Five patients hospitalized from December 18 to December 29, 2019 presented with fever, cough, and dyspnea accompanied by complications of acute respiratory distress syndrome. Chest radiography revealed diffuse opacities and consolidation. One of these patients died. Sequence results revealed the presence of a previously unknown ß-CoV strain in all five patients, with 99.8% to 99.9% nucleotide identities among the isolates. These isolates showed 79.0% nucleotide identity with the sequence of SARS-CoV (GenBank NC_004718) and 51.8% identity with the sequence of MERS-CoV (GenBank NC_019843). The virus is phylogenetically closest to a bat SARS-like CoV (SL-ZC45, GenBank MG772933) with 87.6% to 87.7% nucleotide identity, but is in a separate clade. Moreover, these viruses have a single intact open reading frame gene 8, as a further indicator of bat-origin CoVs. However, the amino acid sequence of the tentative receptor-binding domain resembles that of SARS-CoV, indicating that these viruses might use the same receptor. CONCLUSION: A novel bat-borne CoV was identified that is associated with severe and fatal respiratory disease in humans.


Assuntos
Betacoronavirus , Infecções por Coronavirus/virologia , Pneumonia Viral/virologia , Adulto , Idoso , Betacoronavirus/genética , Betacoronavirus/isolamento & purificação , Infecções por Coronavirus/diagnóstico por imagem , Infecções por Coronavirus/terapia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Pandemias , Pneumonia Viral/diagnóstico por imagem , Pneumonia Viral/terapia , Tomografia por Raios X , Resultado do Tratamento
20.
Chemosphere ; 242: 125273, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31896195

RESUMO

Atmospheric processing may significantly increase solubility of iron in mineral dust, but the effects of heterogeneous reactions on iron solubility have been poorly understood. In this work, we investigated heterogeneous reaction of NO2 (15 ±â€¯1 and 2.5 ±â€¯0.1 ppmv, equal to ∼3.7 × 1014 and ∼6.2 × 1013 molecule cm-3) with hematite, magnetite and goethite at different relative humidities (RH, 0-90%), and changes in particulate nitrate and soluble iron due to heterogeneous reaction with NO2 were quantified as a function of time (up to 24 h). After reaction with 2.5 ±â€¯0.1 ppmv NO2 for 24 h (or less time), hematite and magnetite were fully saturated, while goethite was only partly deactivated. Nitrate yield was largest for goethite, and the mass ratio of formed nitrate to unreacted mineral only reached ∼1% or less after 24 h reaction. All the three minerals showed low reactivities towards NO2, and the average reactive uptake coefficients of NO2 in the first 3 h were found to be < 5 × 10-8. In addition, the increase in iron solubility was found to be small and in some cases even insignificant for the three minerals after heterogeneous reaction with NO2 for 24 h. Overall, the impacts of heterogeneous reaction of NO2 with hematite, magnetite and goethite on nitrate aerosol formation and iron solubility could be very limited.


Assuntos
Compostos Férricos/química , Óxido Ferroso-Férrico/química , Compostos de Ferro/química , Ferro/química , Minerais/química , Nitratos/análise , Óxidos de Nitrogênio/química , Aerossóis , Poluentes Atmosféricos/análise , Poluentes Atmosféricos/química , Poeira/análise , Modelos Químicos , Solubilidade
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