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1.
Biosens Bioelectron ; 201: 113966, 2022 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-35016110

RESUMO

Due to the pore size limitation of single α-hemolysin (α-HL) nanopore sensing interface, ssDNA with secondary conformations can only pass through the nanopore after unzipping as linear ssDNA. For hairpin DNA, a tail with 15-50 bases was usually added to the stem terminal (5' or 3') to facilitate the capture rate and unzipping process, and the typical translocation signal behaves as a square wave with a short dip at the end of the pulse. In this work, the pulse signal of native kanamycin aptamer, a hairpin DNA without the added long tail, was investigated with the single nanopore sensing interface, and different current pulse pattern was observed. The pulse signal exhibited two precise current levels with significantly extended duration of the second, and both duration of the two levels correlate to the interaction of the aptamer to kanamycin. Moreover, the pulse signal not only reveals the selectivity of the aptamer to its target, but also sensitive to the loop sequence change of the aptamer. This work shows that a single nanopore sensing interface could be used as a unique alternative means for interaction investigation of hairpin DNA aptamer without labeling or adding the extra-long tail.

2.
Value Health ; 25(1): 77-83, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-35031102

RESUMO

OBJECTIVES: The incidence and mortality of breast cancer have been increasing in China and bring heavy economic burdens to patients, families, and society. This study aimed to analyze the structure and influencing factors of inpatient expenditures of patients with breast cancer and put forward suggestions for insurance management. METHODS: A multistage stratified random sampling method was used to investigate 379 medical institutions and 7366 pieces of inpatient records of patients with breast cancer in Dalian in 2018. Under the framework of "System of Health Accounts 2011," the current curative expenditure (CCE) and its distribution were calculated. The relationships between hospitalization expenditure and factors were analyzed by multiple stepwise regression and structural equation modeling. RESULTS: The CCE of patients with breast cancer in Dalian in 2018 was ¥273.38 million, accounting for 10.66% of the total expenditure on cancer. The majority of the CCE flowed to large general hospitals. The CCE was concentrated in patients aged 40 to 69 years (23.46%). The hospitalization expenditure correlated positively with length of stay, surgery, and drug expenses (rs = 0.586-0.754, P < .01) and negatively associated with age (rs = -0.074, P < .01). The length of stay mediated the relationship between surgery and hospitalization expenses for patients with breast cancer. The factors that affected the hospitalization expenditure were the drug expenses, surgery, length of stay, insurance status, and institution level. CONCLUSIONS: The cost control for CCE of breast cancer inpatient treatment is crucial in China. Promoting hierarchical diagnosis and treatment, reducing the length of stay, and improving medical insurance depth would be effective measures to reduce the financial burden of patients.

3.
Food Chem ; 367: 130667, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34339981

RESUMO

The main purpose of the present study was to investigate the effect of different fertilizers on the physicochemical properties, multi-element and volatile composition of cucumbers. All samples were divided into five groups according to different combinations and amounts of chicken manure, NPK 17-17-17 fertilizer and microbial fertilizer. The co-application of chicken manure (120,000 kg/ha) and NPK 17-17-17 fertilizer (750 kg/ha) achieved the best texture properties, whereas the addition of the microbial fertilizer at 6000 kg/ha significantly improved the color quality of cucumbers. Similarly, the co-application of chicken manure, NPK 17-17-17 fertilizer and microbial fertilizer at 6000 kg/ha enhanced the number and abundance of volatile components detected in the cucumbers. Cucumbers from the control group contained the highest levels of most of the determined elements. Overall, a combination of chicken manure, NPK 17-17-17 fertilizer and 6000 kg/ha microbial fertilizer is recommended as a relatively efficient fertilizer utilization for cucumbers.


Assuntos
Cucumis sativus , Fertilizantes , Agricultura , Fertilizantes/análise , Esterco , Solo
4.
J Virol ; : JVI0168821, 2021 Dec 08.
Artigo em Inglês | MEDLINE | ID: mdl-34878807

RESUMO

Human herpesvirus 6 (HHV-6) belongs to the betaherpesvirus subfamily and is divided into two distinct species, HHV-6A and HHV-6B. HHV-6 can infect nerve cells and is associated with a variety of nervous system diseases. Recently, the association of HHV-6A infection with Alzheimer's disease (AD) has been suggested. The main pathological phenomena of AD are the accumulation of ß-amyloid (Aß), neurofibrillary tangles, and neuroinflammation, however, the specific molecular mechanism of pathogenesis of AD is not fully clear. In this study, we focused on the effect of HHV-6A U4 gene function on Aß expression. Co-expression of HHV-6A U4 with APP resulted in inhibition of ubiquitin-mediated proteasomal degradation of amyloid precursor protein (APP). Consequently, accumulation of ß-amyloid peptide (Aß), insoluble neurofibrillary tangles, and loss of neural cells may occur. Immunoprecipitation coupled to mass spectrometry (IP-MS) showed that HHV-6A U4 protein interacts with E3 ubiquitin ligase composed of DDB1 and Cullin 4B which is also responsible for APP degradation. We hypothesize that HHV-6A U4 protein competes with APP for binding to E3 ubiquitin ligase, resulting in inhibition of APP ubiquitin modification and clearance. Finally, this is leading to the increase of APP expression and Aß deposition, which is the hallmark of AD. These findings provide novel evidence for the etiological hypothesis of AD that can contribute to the further analysis of HHV-6A role in AD. IMPORTANCE The association of HHV-6A infection with Alzheimer's disease has attracted increasing attention, although its role and molecular mechanism remain to be established. Our results here indicate that HHV-6A U4 inhibits APP (amyloid precursor protein) degradation. U4 protein interacts with CRLs (Cullin-RING E3 ubiquitin-protein ligases) which is also responsible for APP degradation. We propose a model that U4 competitively binds to CRLs with APP, resulting in APP accumulation and Aß generation. Our findings provide new insights into the etiological hypothesis of HHV-6A in AD that can help further analyses.

5.
Food Chem ; 374: 131751, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-34883431

RESUMO

The main purpose of the present study was toinvestigate the influence of genotypes on the volatile, flavonoid-related compounds and antioxidant capacities of chilli peppers. A set of 49 volatiles were identified in the chilli peppers using gas chromatography-ion mobility spectrometry (GC-IMS). The flavonoid-related profiles were established by the simultaneous LC-MS measurement of 38 compounds. The results of chemometrics analysis reveal that Jize and Korean chilli peppers can be distinctly separated from each other. A panel of 18 volatile and 13 flavonoid-related variables with VIP > 1 and p < 0.05 were determined as the discriminants for Jize and Korean chilli peppers. Moreover, Korean chilli peppers showed significantly (p < 0.05) higher antioxidant activity than Jize chilli peppers. A clear and positive correlation was observed between the antioxidant potential and individual flavonoid compounds. The current findings could facilitate the valorization of chilli peppers as bioactive and functional ingredients at various commercial levels.

6.
Sensors (Basel) ; 21(23)2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-34884052

RESUMO

Optical humidity sensors have evolved through decades of research and development, constantly adapting to new demands and challenges. The continuous growth is supported by the emergence of a variety of optical fibers and functional materials, in addition to the adaptation of different sensing mechanisms and optical techniques. This review attempts to cover the majority of optical humidity sensors reported to date, highlight trends in design and performance, and discuss the challenges of different applications.

7.
ACS Appl Mater Interfaces ; 13(51): 61078-61087, 2021 Dec 29.
Artigo em Inglês | MEDLINE | ID: mdl-34905687

RESUMO

Various copper-ceria-based composites have attracted attention as efficient catalysts for the reduction of NO with CO. In this comparative study, we have examined the catalytic potential of different configurations of copper oxide-ceria catalysts, including catalysts based on a copper-ceria solid solution, copper oxide particles supported on ceria, and ball-milled copper oxide-ceria. The structurally different interfaces between the constituents of these catalysts afforded very different catalytic performances. The solid solution catalyst outperformed the corresponding ceria-supported and ball-milled CuO-CeO2 catalysts. The copper cations incorporated into the ceria lattice strongly improved the activity, N2 selectivity, and water vapor tolerance compared to the other catalyst configurations. The experimental observations are supported by first-principles density functional theory (DFT) studies of the reaction pathway, which indicate that the incorporation of Cu cations into the ceria matrix lowers the energy required for activating the lattice oxygen, thereby enhancing the formation and healing of oxygen vacancies, and thus promoting NO reduction with CO.

8.
Artigo em Inglês | MEDLINE | ID: mdl-34948716

RESUMO

In this paper, coconut shell biochar (BC), pickling biochar (HBC), and nano-zero-valent iron-loaded biochar (nZVI-HBC) were prepared; these were used to remove oxytetracycline (OTC), and the removal mechanism and degradation product were analyzed. These biochars were characterized using SEM, XRD, FTIR, and XPS. The effects of biochar addition amount, pH, ion type, and ion concentration on OTC adsorption were studied by a batch adsorption experiment. Under the optimal conditions, the equilibrium adsorption capacity of nZVI-HBC to OTC was 196.70 mg·g-1. The adsorption process can be described by Langmuir isothermal adsorption equations, conforming to the pseudo-second-order dynamics model, indicating that adsorption is dominated by single-molecule chemical adsorption, and a spontaneous process of increasing heat absorption entropy. Mass spectrometry showed that the OTC removal process of nZVI-HBC included not only adsorption but also degradation. These results provide a practical and potentially valuable material for the removal of OTC.


Assuntos
Oxitetraciclina , Poluentes Químicos da Água , Adsorção , Carvão Vegetal , Cocos , Ferro , Poluentes Químicos da Água/análise
9.
Curr Opin Pediatr ; 2021 Nov 24.
Artigo em Inglês | MEDLINE | ID: mdl-34840250

RESUMO

PURPOSE OF REVIEW: Pediatric short stature poses severe concerns to the patient, parents, and physicians. Management for pediatric short stature is still widely debated due to heterogenous etiological factors and treatment options. This review will address the approach to pediatric short stature, commonly within the subset of skeletal dysplasia resulting in disproportionate short stature. The following will be discussed: the etiology, clinical, and radiological evaluations, and management for pediatric short stature. RECENT FINDINGS: Early recognition of short stature and appropriate referrals is shown to benefit the patient and reduce parental concern. A multidisciplinary team, comprising an orthopedic surgeon, is fundamental to provide holistic care and ensure overall good quality of life. Advancements in clinical diagnostic tools and diversified treatment modalities today provides optimism in managing pediatric short stature. SUMMARY: Skeletal dysplasia can be treated with good prognosis if diagnosed and managed early. Thorough clinical, radiological, laboratory, and even genetic investigations are important to differentiate and manage various types of skeletal dysplasia. Our review will provide a comprehensive and up-to-date approach to skeletal dysplasia for pediatric orthopedic surgeons, and indications for physicians to refer patients with suspected short stature to pediatric orthopedic surgeons.

10.
ACS Appl Mater Interfaces ; 13(47): 56485-56497, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-34787994

RESUMO

In this work, MXene Ti3C2Tx-derived nitrogen-functionalized heterophase TiO2 homojunctions (N-MXene) were prepared via the urea-involved solvothermal treatment with varying reaction time as the sensing layer to detect trace NH3 gas at room temperature (20 °C). Compared with no signal for the pristine MXene counterpart, the 18 h-treated sensors (N-MXene-18) achieved a detection limit of 200 ppb with an inspiring response that was 7.3% better than the existing MXene-involved reports thus far. Also, decent repeatability, stability, and selectivity were demonstrated. It is noteworthy that the N-MXene-18 sensors delivered a stronger response, more sufficient recovery, and quicker response/recovery speeds under a humid environment than those under dry conditions, proving the significance of humidity. Furthermore, to suppress the effect of the fluctuation of humidity on NH3 sensing during the tests, a commercial waterproof polytetrafluoroethylene (PTFE) membrane was anchored onto the sensing layer, eventually bringing about humidity-independent features. Both nitrogen doping and TiO2 homojunctions constituted by mixed anatase and rutile phases were primarily responsible for the performance improvement with respect to pristine MXene. This work showcases the enormous potential of N-MXene materials in trace NH3 detection and offers an alternative strategy to realize both heteroatom doping and partial oxidation of MXene that is applicable in future optoelectronic devices.

11.
Ann Transl Med ; 9(20): 1597, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34790803

RESUMO

Objective: To discover potential predictors and explore how to build better models by summarizing the existing prognostic prediction models of non-small cell lung cancer (NSCLC). Background: Research on clinical prediction models of NSCLC has experienced explosive growth in recent years. As more predictors of prognosis are discovered, the choice of predictors to build models is particularly important, and in the background of more applications of next-generation sequencing technology, gene-related predictors are widely used. As it is more convenient to obtain samples and follow-up data, the prognostic model is preferred by researchers. Methods: PubMed and the Cochrane Library were searched using the items "NSCLC", "prognostic model", "prognosis prediction", and "survival prediction" from 1 January 1980 to 5 May 2021. Reference lists from articles were reviewed and relevant articles were identified. Conclusions: The performance of gene-related models has not obviously improved. Relative to the innovation and diversity of predictors, it is more important to establish a highly stable model that is convenient for clinical application. Most of the prevalent models are highly biased and referring to PROBAST at the beginning of the study may be able to significantly control the bias. Existing models should be validated in a large external dataset to make a meaningful comparison.

12.
Cell Rep ; 37(5): 109931, 2021 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-34731621

RESUMO

N-type voltage-gated calcium (CaV) channels mediate Ca2+ influx at presynaptic terminals in response to action potentials and play vital roles in synaptogenesis, release of neurotransmitters, and nociceptive transmission. Here, we elucidate a cryo-electron microscopy (cryo-EM) structure of the human CaV2.2 complex in apo, ziconotide-bound, and two CaV2.2-specific pore blockers-bound states. The second voltage-sensing domain (VSD) is captured in a resting-state conformation, trapped by a phosphatidylinositol 4,5-bisphosphate (PIP2) molecule, which is distinct from the other three VSDs of CaV2.2, as well as activated VSDs observed in previous structures of CaV channels. This structure reveals the molecular basis for the unique inactivation process of CaV2.2 channels, in which the intracellular gate formed by S6 helices is closed and a W-helix from the domain II-III linker stabilizes closed-state inactivation. The structures of this inactivated, drug-bound complex lay a solid foundation for developing new state-dependent blockers for treatment of chronic pain.

13.
Stud Health Technol Inform ; 285: 124-129, 2021 Oct 27.
Artigo em Inglês | MEDLINE | ID: mdl-34734862

RESUMO

In this paper, we propose a health data sharing infrastructure which aims to empower a democratic health data sharing ecosystem. Our project, named Health Democratization (HD), aims to enable seamless data mobility of health data across trust boundaries, through addressing structural and functional challenges of its underlying infrastructure with a throughout core concept of data democratization. A programmatic design of HD platform was elaborated, followed by an introduction about one of our exploratory designs -an "reverse onus" mechanism that aims to incentivize creditable data accessing behaviors. This scheme shows a promising prospect of enabling a democratic health data sharing platform.


Assuntos
Disseminação de Informação , Confiança
14.
Front Pharmacol ; 12: 744494, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34603057

RESUMO

Acinetobacter baumannii is an opportunistic pathogen predominantly associated with nosocomial infections. With emerging resistance against polymyxins, synergistic combinations of drugs are being investigated as a new therapeutic approach. Capsaicin is a common constituent of the human diet and is widely used in traditional alternative medicines. The present study evaluated the antibacterial activities of capsaicin in combination with colistin against three unrelated colistin-resistant Acinetobacter baumannii strains in vitro and in vivo, and then further studied their synergistic mechanisms. Using the checkerboard technique and time-kill assays, capsaicin and colistin showed a synergistic effect on colistin-resistant A. baumannii. A mouse bacteremia model confirmed the in vivo effects of capsaicin and colistin. Mechanistic studies shown that capsaicin can inhibit the biofilm formation of both colistin-resistant and non-resistant A. baumannii. In addition, capsaicin decreased the production of intracellular ATP and disrupted the outer membrane of A. baumannii. In summary, the synergy between these drugs may enable a lower concentration of colistin to be used to treat A. baumannii infection, thereby reducing the dose-dependent side effects. Hence, capsaicin-colistin combination therapy may offer a new treatment option for the control of A. baumannii infection.

15.
Open Med (Wars) ; 16(1): 1386-1394, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34611549

RESUMO

Background: miR-92a is believed to have a significant role in the diagnosis and prognosis of different types of tumors, but the potential impact of its expression is still controversial due to the sample size. We conducted the meta-analysis to figure out whether miR-92a could be used as a detecting tool for assessing the prognosis of gastric cancer. Method: A literature search was conducted by retrieving the Web of Science, PubMed, EMBASE, Chinese National Knowledge Infrastructure, VIP (Technology of Chongqing databases), and Wanfang databases (last updated by February 2020). The sensitivity (SEN), specificity (SPE), positive and negative likelihood ratios (PLR and NLR), diagnostic odds ratio (DOR), and area under the ROC curve (AUC) were pooled to explore the diagnostic performance of miR-92a. The pooled hazard ratios (HRs) and 95% CIs of miR-92a for overall survival (OS) were calculated to explore the prognostic performance of miR-92a. Results: Nine articles containing 11 studies were included. The pooled SEN and SPE were 0.76 and 0.79. Besides, the pooled PLR and NLR were 3.7 and 0.30, and the pooled DOR was 12. AUC was 0.84, indicating a significant value of miR-92a in gastric cancer detection. For the prognostic analysis of miR-92a in gastric cancer, the univariate and multivariate data's poor OS were 1.37 and 2.01. Conclusion: The present meta-analysis demonstrated that miR-92a could be a potential biomarker for the detection of gastric cancer. miR-92a could also be used as a valuable indicator for predicting the prognosis of gastric cancer patients.

16.
Environ Sci Technol ; 55(20): 13718-13727, 2021 10 19.
Artigo em Inglês | MEDLINE | ID: mdl-34623137

RESUMO

Photolysis of oxygenated volatile organic compounds (OVOCs) produces a primary source of free radicals, including OH and inorganic and organic peroxy radicals (HO2 and RO2), consequently increasing photochemical ozone production. The amplification of radical cycling through OVOC photolysis provides an important positive feedback mechanism to accelerate ozone production. The large production of OVOCs near the surface helps promote photochemistry in the whole boundary layer. This amplifier effect is most significant in regions with high nitrogen oxides (NOx) and VOC concentrations such as Wangdu, China. Using a 1-D model with comprehensive observations at Wangdu and the Master Chemical Mechanism (MCM), we find that OVOC photolysis is the largest free-radical source in the boundary layer (46%). The condensed chemistry mechanism we used severely underestimates the OVOC amplifier effect in the boundary layer, resulting in a lower ozone production rate sensitivity to NOx emissions. Due to this underestimation, the model-simulated threshold NOx emission value, below which ozone production decreases with NOx emission decrease, is biased low by 24%. The underestimated OVOC amplifier effect in a condensed mechanism implies a low bias in the current 3-D model-estimated efficacy of NOx emission reduction on controlling ozone in polluted urban and suburban regions of China.


Assuntos
Poluentes Atmosféricos , Ozônio , Compostos Orgânicos Voláteis , Poluentes Atmosféricos/análise , Monitoramento Ambiental , Óxidos de Nitrogênio/análise , Ozônio/análise , Compostos Orgânicos Voláteis/análise
17.
J Chem Phys ; 155(13): 134704, 2021 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-34624982

RESUMO

Mixed ionic/electronic conductors (MIECs) are desirable materials for next-generation electronic devices and energy storage applications. Polymeric MIECs are attractive from the standpoint that their structure can be controlled and anticipated to have mechanically robust properties. Here, we prepare and investigate conjugated copolymers containing thiophene and selenophene repeat units and their homopolymer counterparts. Specifically, thiophene bearing a triethylene glycol (EG3) side chain was polymerized and copolymerized with dodecyl thiophene/selenophene monomers. The synthesis leads to a class of copolymers that contain either S or Se and are blocky in nature. The Li-ion conductivity of ionically doped copolymers, P3DDT-s-P3(EG3)T and P3DDS-s-P3(EG3)T (9.7 × 10-6 and 8.2 × 10-6 S/cm, respectively), was 3-4 fold higher than that of the ionically doped constituent homopolymer, P3(EG3)T (2.2 × 10-6 S/cm), at ambient conditions. The electronic conductivity of the oxidatively doped copolymers was significantly higher than that of the constituent homopolymer P3(EG3)T, and most notably, P3DDS-s-P3(EG3)T reached ∼7 S/cm, which is the same order of magnitude as poly(3-dodecylthiophene) and poly(3-dodecylselenophene), which are the highest oxidatively doped conductors based on control experiments. Our findings provide implications for designing new MIECs based on copolymerization and the incorporation of heavy atom heterocycles.

18.
Nanotechnology ; 33(6)2021 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-34706350

RESUMO

The irrational NH3emission routinely poses a significant threat to human health and environmental protection even at low dose. In addition, high miniaturization and low power-consumption has been the critical requirements of Internet of Things. To meet these demands, it is greatly pressing to develop a novel gas sensor with the capability to detect trace NH3without external heating or light-irradiation elements. In this work, the organic conducting conjugated polymer PEDOT:PSS was combined with inorganic nitrogen-doped transition metal carbides and nitrides (N-MXene Ti3C2Tx) for chemiresistive NH3sensing at room temperature (20oC). By means of the organic-inorganicn-pheterojunctions via the synergistic effect, the results show that the composite film sensor with the optimal mass ratio of 1:0.5 between N-MXene and PEDOT:PSS components delivered favorable NH3sensing performance than individual N-MXene or PEDOT:PSS counterparts in terms of higher response and quicker response/recovery speeds under 20oC@36%RH air. Besides, decent repeatability, stability and selectivity were demonstrated. The incorporated N atoms served as excellent electron donors to promote the electron-transfer reactions and augment the sorption sites. Simultaneously, partial oxidation of MXene brought about some TiO2nanoparticles which acted as spacers to widen the interlayer spacing and probably suppress the MXene restacking during the film deposition, thus favoring the gas diffusion/penetration within the sensing layer and then a quick reaction kinetic. The modulation of consequent build-in field within the heterojunctions was responsible for the reversible NH3sensing. In addition, pre-adsorbed water molecules facilitated to establish a swift adsorption/desorption balance. The proposed strategy expanded the application range of MXene based composite materials and enrich the current sensing mechanisms of NH3gas sensors.

19.
Elife ; 102021 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-34468314

RESUMO

The ability to produce outer membrane projections in the form of tubular membrane extensions (MEs) and membrane vesicles (MVs) is a widespread phenomenon among diderm bacteria. Despite this, our knowledge of the ultrastructure of these extensions and their associated protein complexes remains limited. Here, we surveyed the ultrastructure and formation of MEs and MVs, and their associated protein complexes, in tens of thousands of electron cryo-tomograms of ~90 bacterial species that we have collected for various projects over the past 15 years (Jensen lab database), in addition to data generated in the Briegel lab. We identified outer MEs and MVs in 13 diderm bacterial species and classified several major ultrastructures: (1) tubes with a uniform diameter (with or without an internal scaffold), (2) tubes with irregular diameter, (3) tubes with a vesicular dilation at their tip, (4) pearling tubes, (5) connected chains of vesicles (with or without neck-like connectors), (6) budding vesicles and nanopods. We also identified several protein complexes associated with these MEs and MVs which were distributed either randomly or exclusively at the tip. These complexes include a secretin-like structure and a novel crown-shaped structure observed primarily in vesicles from lysed cells. In total, this work helps to characterize the diversity of bacterial membrane projections and lays the groundwork for future research in this field.


Assuntos
Bactérias/ultraestrutura , Proteínas da Membrana Bacteriana Externa/ultraestrutura , Membrana Externa Bacteriana/ultraestrutura , Extensões da Superfície Celular/ultraestrutura , Microscopia Crioeletrônica , Tomografia com Microscopia Eletrônica , Bactérias/classificação , Complexos Multiproteicos
20.
Environ Sci Technol ; 55(19): 12852-12861, 2021 10 05.
Artigo em Inglês | MEDLINE | ID: mdl-34546042

RESUMO

Background ozone in this study is defined as the amount of ozone that is not affected by the emissions of ozone precursors in the region of study and is transported from the distant troposphere or the stratosphere. It is one of the factors that must be considered in regional ozone control strategies. Different methods have been applied to define the background ozone level. We develop a new method based on the O3-CO-HCHO relationships, which can be applied to both observation and modeling data for regions with high isoprene emission ozone, such as the Southeast United States. We make use of the extensive aircraft and surface observations in the Southeast in the summer of 2013. Compared to the diagnostic results using the relationship of O3-NOz (total reactive nitrogen excluding nitrogen oxides), zero-emission (model-only), and 5th percentile methods, the new method is most consistent using observation or model data and the resulting background ozone concentrations are 4-50% lower than the other methods for field campaigns. Using this method, we find that the summertime background ozone at the surface is in the range of 10-15 ppbv in the inland areas of the Southeast, which is lower than that reported in previous studies. This background ozone tends to increase from urban centers to rural regions and from the surface to higher altitude due to changing ozone lifetime driven by anthropogenic emissions and dry deposition to the surface. The better quantification of background ozone using the new method highlights the importance of the contributions by natural emissions to ozone and the necessity to control anthropogenic emissions in ozone nonattainment areas of the Southeast.


Assuntos
Poluentes Atmosféricos , Ozônio , Poluentes Atmosféricos/análise , Monitoramento Ambiental , Óxidos de Nitrogênio/análise , Ozônio/análise , Estações do Ano , Sudeste dos Estados Unidos , Estados Unidos
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