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1.
Pharmacol Ther ; : 107696, 2020 Oct 03.
Artigo em Inglês | MEDLINE | ID: mdl-33022301

RESUMO

Artemisinin and its derivatives are the most effective antimalarial drugs. Besides anti-malarial activity, artemisinin and its derivatives have displayed wide-spectrum bioactivities such as anti-parasite, anti-tumor, and anti-obesity effects. Obesity is an epidemic worldwide which is a big threat to human health, but there are only a few approved anti-obesity drugs in the world. Also, these drugs are efficient to limited patients partly because their safety and efficacy are questioned. Anti-inflammatory therapies may be valuable in obesity treatment since growing evidence shows chronic metabolic inflammation is implicated in metabolic disease pathogenesis. As artemisinin and its derivatives display effective anti-inflammatory and immunoregulatory properties with less toxicity, it provides an insight for novel drug development in obesity therapeutic strategies via immune-regulatory mechanisms. In this review, the potential of artemisinin and its derivatives to treat various metabolic diseases such as obesity and diabetes is discussed.

2.
Cell Transplant ; 29: 963689720965182, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33028104

RESUMO

Long noncoding RNAs (lncRNAs) are crucial regulatory molecules involved in diverse biological processes and human diseases, including preeclampsia (PE). The lncRNA growth arrest associated lncRNA 1 (GASAL1) has been implicated in multiple malignant solid tumors and other diseases, while it is poorly known as the potential molecular mechanism of GASAL1 in PE. In this study, GASAL1 was significantly downregulated in the placentas' of tissues from primipara with PE and trophoblast cell lines. Then, the upregulation of GASAL1 dramatically decreased proliferation and invasion and enhanced apoptosis in HTR-8/SVneo and JAR cells. Bioinformatics tool predicated that there is a potential interaction between GASAL1 and serine/arginine splicing factor 1 (SRSF1). RNA pull-down assays showed that GASAL1 directly binds with SRSF1 that could promote cell proliferation and invasion and suppress cell apoptosis. Further research showed that promoting effects of trophoblasts proliferation and invasion caused by co-transfecting GASAL1 and SRSF1 into HTR-8/SVneo and JAR cells were impaired by SRSF1 knockdown. Moreover, inhibition of the mammalian target of rapamycin (mTOR) activity by rapamycin influenced the effects of GASAL1 on cell proliferation, invasion, and apoptosis. Taken together, these findings suggest that lncRNA GASAL1 interacts with SRSF1 to regulate the proliferative, invasive, and apoptotic abilities of trophoblast cells via the mTOR signaling pathway.

3.
Environ Sci Technol ; 54(19): 11818-11826, 2020 Oct 06.
Artigo em Inglês | MEDLINE | ID: mdl-32876440

RESUMO

Isocyanic acid (HNCO) is a potentially toxic atmospheric pollutant, whose atmospheric concentrations are hypothesized to be linked to adverse health effects. An earlier model study estimated that concentrations of isocyanic acid in China are highest around the world. However, measurements of isocyanic acid in ambient air have not been available in China. Two field campaigns were conducted to measure isocyanic acid in ambient air using a high-resolution time-of-flight chemical ionization mass spectrometer (ToF-CIMS) in two different environments in China. The ranges of mixing ratios of isocyanic acid are from below the detection limit (18 pptv) to 2.8 ppbv (5 min average) with the average value of 0.46 ppbv at an urban site of Guangzhou in the Pearl River Delta (PRD) region in fall and from 0.02 to 2.2 ppbv with the average value of 0.37 ppbv at a rural site in the North China Plain (NCP) during wintertime, respectively. These concentrations are significantly higher than previous measurements in North America. The diurnal variations of isocyanic acid are very similar to secondary pollutants (e.g., ozone, formic acid, and nitric acid) in PRD, indicating that isocyanic acid is mainly produced by secondary formation. Both primary emissions and secondary formation account for isocyanic acid in the NCP. The lifetime of isocyanic acid in a lower atmosphere was estimated to be less than 1 day due to the high apparent loss rate caused by deposition at night in PRD. Based on the steady state analysis of isocyanic acid during the daytime, we show that amides are unlikely enough to explain the formation of isocyanic acid in Guangzhou, calling for additional precursors for isocyanic acid. Our measurements of isocyanic acid in two environments of China provide important constraints on the concentrations, sources, and sinks of this pollutant in the atmosphere.

4.
Clin Hemorheol Microcirc ; 76(2): 317-327, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32925012

RESUMO

BACKGROUND: Keratinocytes are exposed to a thermal gradient throughout epidermal layers in human skin depending on environmental temperatures. OBJECTIVE: Here, the effect of cyclic temperature changes (ΔT) on HaCaT cell behaviors was explored. METHODS: HaCaT cells were cultured at constant temperature (37 °C or 25 °C) or under ΔT conditions. The morphology, mechanics, cell cycle progression, proliferation, and lipid synthesis of HaCaT cells were determined. RESULTS: ΔT conditions led to the inhomogeneous arrangement of the cytoskeleton in HaCaT cells, which resulted in enlarged size, rounder shape, and increased stiffness. Accumulation in the G2/M phase in the cell cycle, a decreased proliferation rate, and a delayed lipogenesis were detected in HaCaT cells cultured under ΔT conditions. CONCLUSIONS: ΔT conditions resulted in the re-arrangement of the cytoskeleton in HaCaT cells, which showed similarity to the temperature-induced disassemble and re-assemble of cytoskeletons in keratinocyte in vivo. The altered cytoskeleton arrangement resulted in the cell enlargement and stiffening, which reflected the changes in cellular functions. The application of oscillatory temperature in the in vitro culture of keratinocytes provides a way to gain more insights into the role of skin in response to environmental stimuli and maintaining its homeostasis in vivo.

5.
Clin Hemorheol Microcirc ; 76(2): 329-340, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32925021

RESUMO

BACKGROUND: The formation of spheroids is tightly regulated by intrinsic cell-cell and cell-substrate interactions. OBJECTIVE: The chitosan (CS)-coating was applied to investigate the driven force directed the spheroid formation. METHODS: The effects of CS on cell functions were studied. Atomic force microscopy was employed to measure the cell- biomaterial interplay at single cell level. RESULTS: HaCaT cells shifted from their flattened sheet to a compact 3D spheroidal morphology when increasing CS-coating concentration. The proliferative capacity of HaCaT was preserved in the spheroid. The expression and activation of integrin ß1 (ITGB1) were enhanced on CS modified surfaces, while the active to total ratio of ITGB1 was decreased. The adhesive force of a single HaCaT cell to the tissue culture plate (TCP) was 4.84±0.72 nN. It decreased on CS-coated surfaces as CS concentration increased, from 2.16±0.26 nN to 0.96±0.17 nN. The adhesive force between the single HaCaT cell to its neighbor cell increased as CS concentration increased, from 1.15±0.09 nN to 2.60±0.51 nN. CONCLUSIONS: Conclusively, the decreased cell- substrate adhesion was the main driven force in the spheroid formation. This finding might serve as a design criterion for biomaterials facilitating the formation of epithelial spheroids.

6.
Ann Thorac Surg ; 2020 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-32805271

RESUMO

BACKGROUND: To summarize the safety and effect of minimally invasive surgery for hypertrophic obstructive cardiomyopathy (HOCM) with significant mitral regurgitation through a single transaortic approach via right minithoracotomy. METHODS: From 2008 to 2017, 51 HOCM patients with significant mitral regurgitation underwent minimally invasive surgery via right minithoractomy. Preoperative peak left ventricular outflow tract pressure gradient (LVOTPG) was 96.53±28.72mmHg. Preoperative average interventricular septum thickness was 24.31±3.52mm. All patients had significant mitral regurgitation with systolic anterior motion phenomenon. An oblique incision was made on anterior wall of ascending aorta or aortic root. Modified Morrow procedure and edge-to-edge mitral valvuloplasty were performed through the single transaortic approach via right minithoractomy. RESULTS: All patients successfully underwent the minimally invasive surgery through the single transaortic approach via right minithoractomy. At discharge, postoperative peak LVOTPG (18.16±6.41mmHg) and interventricular septum thickness (14.33±1.99mm) were significantly decreased compared with preoperative values (P<0.05). All patients had none or trivial mitral regurgitation. The average peak mitral valve pressure gradient was 3.39±1.82mmHg. Systolic anterior motion phenomenon disappeared in all patients. During follow-up, peak LVOTPG was 19.27±6.10mmHg; average interventricular septum thickness was 14.67±1.87mm. All patients had none or trivial mitral regurgitation. Average peak mitral valve pressure gradient was 3.04±1.52mmHg. No systolic anterior motion phenomenon occurred. CONCLUSION: Minimally invasive surgery of modified Morrow procedure and edge-to-edge mitral valvuloplasty through a single transaortic approach via right minithoractomy could be safely and effectively applied for patients with HOCM and significant mitral regurgitation, which could also effectively eliminate systolic anterior motion phenomenon and without mitral valve stenosis.

7.
Pharmacol Ther ; : 107658, 2020 Aug 08.
Artigo em Inglês | MEDLINE | ID: mdl-32777330

RESUMO

As the first-line antimalarial drugs, artemisinins gained wide acceptance after the emergence of resistance to chloroquine in the 1950s. Artemisinin-based drugs have saved lives, especially in developing countries. The discovery of artemisinin was unique, timely, and fascinating, and the benefits of artemisinin were with far-reaching implications. Herein, we will give a brief description of various aspects of the development of artemisinin and discuss the position and perspectives of artemisinin-based drugs.

8.
Asian Cardiovasc Thorac Ann ; 28(7): 416-420, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32854515

RESUMO

Atrial fibrillation is a common clinical arrhythmia with high morbidity and a risk of stroke. The Cox-maze IV procedure that uses radiofrequency energy for ablation is established as an effective way to eliminate atrial fibrillation. Compared to the Cox-maze IV procedure, the video-assisted Wolf mini-maze procedure is associated with reduced surgical trauma, but still requires bilateral thoracotomies, and the ablation line connecting the right and left pulmonary vein isolations cannot be created with a bipolar ablation clamp. We have developed a novel video-assisted mini-maze technique that uses a unilateral (left chest) thoracoscopic approach (the Mei mini-maze procedure).


Assuntos
Fibrilação Atrial/cirurgia , Ablação por Cateter , Veias Pulmonares/cirurgia , Cirurgia Torácica Vídeoassistida , Fibrilação Atrial/diagnóstico , Fibrilação Atrial/fisiopatologia , Ablação por Cateter/efeitos adversos , Frequência Cardíaca , Humanos , Veias Pulmonares/fisiopatologia , Cirurgia Torácica Vídeoassistida/efeitos adversos , Resultado do Tratamento
9.
JAMA Ophthalmol ; 138(10): 1079-1086, 2020 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-32845280

RESUMO

Importance: Ocular manifestations and outcomes in children with confirmed coronavirus disease 2019 (COVID-19), relevant affecting factors, and differences in ocular disease between children and adults have yet to be fully understood. Objective: To investigate ocular manifestations and clinical characteristics of children with laboratory-confirmed COVID-19. Design, Setting, and Participants: This cross-sectional study was conducted at Wuhan Children's Hospital in Wuhan, China. Children with COVID-19 confirmed by severe acute respiratory syndrome coronavirus disease 2 nucleic acid tests of upper respiratory tract specimens between January 26 and March 18, 2020, were included. Main Outcomes and Measures: Onset clinical symptoms and duration, ocular symptoms, and needs for medication. Results: A total of 216 pediatric patients were included, among whom 134 (62%) were boys, with a median (interquartile range) age of 7.25 (2.6-11.6) years. Based on the exposure history, 193 children (89.4%) had a confirmed (173 [80.1%]) or suspected (20 [9.3%]) family member with COVID-19 infection. The most common symptoms among symptomatic children were fever (81 [37.5%]) and cough (79 [36.6%]). Of 216 children, 93 (43.1%) had no systemic or respiratory symptoms. All children with mild (101 [46.8%]) or moderate (115 [53.2%]) symptoms recovered without reported death. Forty-nine children (22.7%) showed various ocular manifestations, of which 9 had ocular complaints being the initial manifestations of COVID-19. The common ocular manifestations were conjunctival discharge (27 [55.1%]), eye rubbing (19 [38.8%]), and conjunctival congestion (5 [10.2%]). Children with systemic symptoms (29.3% vs 14.0%; difference, 15.3%; 95% CI, 9.8%-20.7%; P = .008) or with cough (31.6% vs 17.5%; difference, 14.1%; 95% CI, 8.0%-20.3%; P = .02) were more likely to develop ocular symptoms. Ocular symptoms were typically mild, and children recovered or improved. Conclusions and Relevance: In this cross-sectional study, children hospitalized with COVID-19 in Wuhan, China, presented with a series of onset symptoms including fever, cough, and ocular manifestations, such as conjunctival discharge, eye rubbing, and conjunctival congestion. Patients' systemic clinical symptoms or cough were associated with ocular symptoms. Ocular symptoms recovered or improved eventually.


Assuntos
Betacoronavirus , Infecções por Coronavirus/complicações , Oftalmopatias/etiologia , Pneumonia Viral/complicações , Adolescente , Criança , Pré-Escolar , Estudos Transversais , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Pandemias
10.
Eye (Lond) ; 2020 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-32678349

RESUMO

OBJECTIVES: Primary malignant tumours of the lacrimal sac are rare, surgery and radiotherapy may induce substantial side effects for patients. Here, this article reports an innovative technique of interstitial brachytherapy developed for the treatment of malignant lacrimal sac tumours. PATIENTS AND METHODS: Four patients (male 3, female 1), with an average age of 52.7 years (range 41-72 years), were individually diagnosed with squamous cell carcinoma, adenocarcinoma, adenoid cystic carcinoma and lymphoma. All patients received Iodine-125 interstitial brachytherapy after surgical resection for malignant lacrimal sac tumours. Visual function examination (vision, intraocular tension, fundus photography, fluorescein angiography, and optical coherence tomography) and CT/MRI/PET-MRI were performed to look for signs of recurrent tumours or metastasis. RESULTS: Four patients were followed for an average of 28 months (range, 23-37 months). All patients were free from local disease. Their visual function was normal, and CT/MRI did not reveal any tumour recurrence. CONCLUSIONS: Iodine-125 interstitial brachytherapy can be used as an alternative to wide excision or exenteration of these tumours. There was good local control, reasonable maintenance of vision, and good cosmesis.

11.
ACS Appl Mater Interfaces ; 12(29): 32493-32502, 2020 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-32573191

RESUMO

Combination therapy via stimulus-responsive drug release is known to improve treatment efficacy and minimize side effects. However, the use of low-abundance cancer biomarkers as molecular triggers to induce efficient drug release for combination therapy still remains a challenge. Herein, we developed a dual microRNA-responsive drug nanocarrier for catalytic release of doxorubicin (Dox) and small interfering RNA (siRNA) in cancerous cells for combined chemotherapy and gene therapy with logic operation. The nanocarrier is constructed by assembling two duplexes of DNA/RNA and Dox molecules onto DNA-functionalized gold nanoparticles. Two microRNA molecules (miRNA-21 and miRNA-10b overexpressed in MDA-MB-231) could alternatively catalyze the disassembly of the nanocarrier through a thermodynamically driven entropy gain process, during which Dox molecules are released, and the two pairs of released DNA/RNA duplex hybridize to generate siRNA (siBcl-2) in situ by strand displacement reactions. Quantum dots are used to track the process in living cells. The AND logic gate-based drug release system allows effective treatment of specific cancer cell types according to miRNA expression patterns. This strategy represents an effective means to overcome multidrug resistance and improve therapeutic effects.

12.
BMC Ophthalmol ; 20(1): 236, 2020 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-32552704

RESUMO

BACKGROUND: To explore the effects of enhanced external counterpulsation (EECP) and its underlying influencing factors in nonarteritic anterior ischemic optic neuropathy (NAION) patients. METHODS: Patients at Zhongshan Ophthalmic Center with recent-onset (< 8 weeks) NAION were retrospectively recruited. The patients had decided whether or not they would undergo EECP treatment, and the patients who declined were included in the control group. The effectiveness of EECP was evaluated by comparing the visual function and fellow eye involvement in patients with and without EECP treatment. RESULTS: In total, 61 patients (76 eyes) were included. Twenty-nine patients (37 eyes) underwent EECP treatment, while 32 patients (39 eyes) were included in the control group. Mean time from NAION onset to EECP initiation was 27.59 ± 16.70 days. In the EECP group, the mean EECP duration was 31.57 ± 18.45 days. EECP was well tolerated by all patients. However, there was no significant difference in visual function between the EECP and control groups. Furthermore, there was no evidence of the effectiveness of EECP in the subgroup analysis of patients with different systemic health conditions. Among the 42 patients with monocular NAION, the sequential attack rate was comparable between the EECP (27.78%) and control (25.00%) groups. CONCLUSION: This study is the first nonrandomized controlled study to evaluate the effectiveness of EECP in NAION patients. Unfortunately, we failed to demonstrate the effectiveness of EECP in NAION at the 6-month follow-up. Any further application of EECP in NAION patients should be cautious.

13.
Cell Biochem Funct ; 38(6): 801-809, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32424818

RESUMO

Ovarian cancer (OC) is one of the most common gynaecologic malignancies. Deleted in malignant brain tumors 1 (DMBT1) was considered as a tumour suppressor in multiple cancers, but there have been no systemic profiling studies of DMBT1 in OC until now. The aim of this study is to explore the role and the potential mechanism of DMBT1 in OC. mRNA levels and protein expressions of corresponding genes were detected by quantitative real-time polymerase chain reaction and western blot. Cell proliferation was detected by CCK-8 assay and cell colony formation. Cell migration and invasion were detected by wound healing and transwell assay. The combination between DMBT1 and galectin-3 was demonstrated by immunoprecipitation. We demonstrated that DMBT1 was downregulated in OC cell lines, especially SKOV3 cells. Overexpression of DMBT1 significantly inhibited cell proliferation, colony formation, migration and invasion, as well as decreased Matrix Metalloproteinase-2 (MMP-2) and MMP-7. DMBT1 caused a reduction of cell viability by treatment with cisplatin. Immunoprecipitation assay revealed a combination between DMBT1 and galectin-3. DMBT1 could decrease the expression of galectin-3 and inhibit the phosphorylation of PI3K and AKT, while overexpression of galectin-3 reversed this effect. In summary, DMBT1 might inhibit the progression of OC and improve the sensitivity of SKOV3 cells to cisplatin through galectin-3/PI3K/AKT pathway, giving a new insight into the role of DMBT1 in OC and enriching the potential strategies for OC treatment. SIGNIFICANCE OF THE STUDY: The present study focus on the role and the potential mechanism of DMBT1 in ovarian cancer (OC). We demonstrated that DMBT1 might inhibit the progression of ovarian by inhibiting cell proliferation, migration and invasion and increased the sensitivity to cisplatin through galectin-3/PI3K/AKT pathway. The findings ensure the interaction relation between DMBT1 and galectin-3 in OC, providing a novel biological marker for OC and enriching the potential strategies for OC treatment.

14.
Sci Total Environ ; 734: 139318, 2020 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-32454334

RESUMO

Amino acids are important water-soluble nitrogen-containing compounds in atmospheric aerosols. They can be involved in cloud formation due to their hygroscopicity and have significant influences on the hygroscopicity of inorganic compounds, which have not yet been well characterized. In this work, the hygroscopic properties of three amino acids, including aspartic acid, glutamine, and serine, as well as their mixtures with ammonium sulfate (AS) were investigated using a hygroscopicity tandem differential mobility analyzer (HTDMA) system. The gradual water uptake of aspartic acid, glutamine and serine particles indicates that they exist as liquid phase at low RH. When mixing either aspartic acid or glutamine with AS by mass ratio of 1:3, we observed a clear phase transition but with a lower deliquescence relative humidity (DRH) with respect to that of pure AS. This suggests the crystallization of AS in the presence of each of these two amino acids. However, as the mass fractions of these two amino acids increased in the mixed particles, the deliquescence transition process was not obvious. In contrast, the crystallization of AS was efficiently hampered even at low content (i.e., 25% by mass) of serine in the mixed particles. The Zdanovskii-Stokes-Robinson (ZSR) method in general underestimated the hygroscopic growth of any mixtures at RH below 79% (prior to AS deliquescence), suggesting both amino acid and the partially dissolved AS contributed the overall hygroscopicity at RH in this range. Relatively good agreements were reached between the measurements and model predictions using the Extended Aerosol Inorganic Model (E-AIM) assuming solid state AS in the mixed particles for 1:3 aspartic acid-AS and glutamine-AS systems. However, the model failed to simulate the water uptake behaviors of any other systems. It demonstrates that the interactions between components within the aerosols have a significant effect on the phase state of the mixed particles.


Assuntos
Molhabilidade , Aerossóis , Aminoácidos , Sulfato de Amônio , Água
15.
Signal Transduct Target Ther ; 5(1): 72, 2020 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-32435053

RESUMO

Natural products are an important source of new drugs for the treatment of various diseases. However, developing natural product-based new medicines through random moiety modification is a lengthy and costly process, due in part to the difficulties associated with comprehensively understanding the mechanism of action and the side effects. Identifying the protein targets of natural products is an effective strategy, but most medicines interact with multiple protein targets, which complicate this process. In recent years, an increasing number of researchers have begun to screen the target proteins of natural products with chemical proteomics approaches, which can provide a more comprehensive array of the protein targets of active small molecules in an unbiased manner. Typically, chemical proteomics experiments for target identification consist of two key steps: (1) chemical probe design and synthesis and (2) target fishing and identification. In recent decades, five different types of chemical proteomic probes and their respective target fishing methods have been developed to screen targets of molecules with different structures, and a variety of protein identification approaches have been invented. Presently, we will classify these chemical proteomics approaches, the application scopes and characteristics of the different types of chemical probes, the different protein identification methods, and the advantages and disadvantages of these strategies.

16.
Environ Sci Technol ; 54(10): 5973-5979, 2020 05 19.
Artigo em Inglês | MEDLINE | ID: mdl-32343120

RESUMO

The oxidation of nitric oxide to nitrogen dioxide by hydroperoxy (HO2) and organic peroxy radicals (RO2) is responsible for the chemical net ozone production in the troposphere and for the regeneration of hydroxyl radicals, the most important oxidant in the atmosphere. In Summer 2014, a field campaign was conducted in the North China Plain, where increasingly severe ozone pollution has been experienced in the last years. Chemical conditions in the campaign were representative for this area. Radical and trace gas concentrations were measured, allowing for calculating the turnover rates of gas-phase radical reactions. Therefore, the importance of heterogeneous HO2 uptake on aerosol could be experimentally determined. HO2 uptake could have suppressed ozone formation at that time because of the competition with gas-phase reactions that produce ozone. The successful reduction of the aerosol load in the North China Plain in the last years could have led to a significant decrease of HO2 loss on particles, so that ozone-forming reactions could have gained importance in the last years. However, the analysis of the measured radical budget in this campaign shows that HO2 aerosol uptake did not impact radical chemistry for chemical conditions in 2014. Therefore, reduced HO2 uptake on aerosol since then is likely not the reason for the increasing number of ozone pollution events in the North China Plain, contradicting conclusions made from model calculations reported in the literature.


Assuntos
Ozônio/análise , Aerossóis/análise , Atmosfera , China , Radical Hidroxila
17.
Artigo em Inglês | MEDLINE | ID: mdl-32320195

RESUMO

Nowadays, monitoring and recording CO2 gas has become more and more important in various areas, leading to increasing demand for developing high-sensitive CO2 sensors. In this study, a novel potentiometric CO2 gas sensor is designed based on a new solid electrolyte of Y-doped La9.66Si5.3B0.7O26.14 (Y-LSBO), coated with the Li2CeO3-Au-Li2CO3 composite as a sensing electrode and Pt as a reference electrode. With the optimized composition of a sensing electrode, the electromotive force (EMF) varies linearly with the logarithm of the CO2 concentration in the range of 400-4000 ppm, exhibiting an excellent Nernstian response to CO2 gas in both dry and humid atmospheres. The fabricated CO2 sensor can be well operated at 400 °C in a dry atmosphere and 450 °C in a humid atmosphere. Based on the results, we have proposed that the good CO2 sensing performance may be associated with Li2CeO3 playing a role of "ionic bridge" between the O2- conductor (Y-LSBO) and the Li+ conductor (Li2CO3). This study not only shows the promising potential of a Y-LSBO solid electrolyte utilized in the field of gas sensors but also enriches the research of solid electrolyte-based potentiometric CO2 gas sensors.

18.
Environ Sci Technol ; 54(7): 3849-3860, 2020 04 07.
Artigo em Inglês | MEDLINE | ID: mdl-32131584

RESUMO

Secondary organic aerosol (SOA) constitutes a large fraction of organic aerosol worldwide, however, the formation mechanisms in polluted environments remain poorly understood. Here we observed fast daytime growth of oxygenated organic aerosol (OOA) (with formation rates up to 10 µg m-3 h-1) during low relative humidity (RH, daytime average 38 ± 19%), high RH (53 ± 19%), and fog periods (77 ± 13%, fog occurring during nighttime with RH reaching 100%). Evidence showed that photochemical aqueous-phase SOA (aqSOA) formation dominantly contributed to daytime OOA formation during the periods with nighttime fog, while both photochemical aqSOA and gas-phase SOA (gasSOA) formation were important during other periods with the former contributing more under high RH and the latter under low RH conditions, respectively. Compared to daytime photochemical aqSOA production, dark aqSOA formation was only observed during the fog period and contributed negligibly to the increase in OOA concentrations due to fog scavenging processes. The rapid daytime aging, as indicated by the rapid decrease in m,p-xylene/ethylbenzene ratios, promoted the daytime formation of precursors for aqSOA formation, e.g., carbonyls such as methylglyoxal. Photooxidants related to aqSOA formation such as OH radical and H2O2 also bear fast daytime growth features even under low solar radiative conditions. The simultaneous increases in ultraviolet radiation, photooxidant, and aqSOA precursor levels worked together to promote the daytime photochemical aqSOA formation. We also found that biomass burning emissions can promote photochemical aqSOA formation by adding to the levels of aqueous-phase photooxidants and aqSOA precursors. Therefore, future mitigation of air pollution in a polluted environment would benefit from stricter control on biomass burning especially under high RH conditions.


Assuntos
Poluentes Atmosféricos , Aerossóis , China , Peróxido de Hidrogênio , Raios Ultravioleta
19.
J Pediatr Surg ; 2020 Feb 24.
Artigo em Inglês | MEDLINE | ID: mdl-32171534

RESUMO

BACKGROUND: To investigate the safety of using ABO incompatible (ABO-i) liver grafts in pediatric patients under our prophylactic strategies. METHODS: A total number of 544 pediatric liver transplantations between January 2013 and December 2017 performed in Organ Transplant Center, Tianjin First Central Hospital were included in this study. The recipients were divided into 3 groups based on the compatibility of donor-recipient blood type matching (ABO-identical group, n = 352, ABO-compatible group, n = 121 and ABO-incompatible group, n = 71). Recipient characteristics, perioperative data, postoperative complications and recipient survival rate were compared. The recipient outcomes between living-related and non-living-related ABO-incompatible liver graft recipients were also compared. RESULTS: The median follow-up time in three groups were 3.4 (1.8, 6.4) years, 3.2 (1.8, 6.1) years and 2.8 (1.8, 6.2) years, without statistical difference. The cumulative 1-year and 3-year graft survival rate were 94.3% and 94.0% in ABO-id group, 93.1% and 93.1% in ABO-c group and 97.1% and 97.1% in ABO-i group. The cumulative 1-year and 3-year recipient survival rate were 96.1% and 95.5% in ABO-id group, 94.8% and 94.8% in ABO-c group and 97.1% and 97.1% in ABO-i group, respectively. No significant difference was seen among three groups. The recipient characteristics and perioperative data were similar among three groups. The recipients in ABO-i group showed significantly lower incidence of portal vein stenosis. Apart from that, three groups shared equal incidence of other surgical complications and acute rejection. Among ABO-i liver graft recipients, the cumulative 1-year and 3-year recipient survival rate were 98.2% and 98.2% in living donor liver transplant (LDLT) recipients and 92.9% and 92.9% in deceased donor liver transplant (DDLT) recipients, without significant difference. The incidence of hepatic artery thrombosis was significantly higher in DDLT group compared with LDLT group, while the other complications were similar between two groups. CONCLUSION: Our data revealed that the application of ABO-i liver grafts in pediatric liver transplantation under rational peri-operative management strategy is a safe measure to increase donor availability for pediatric patients in Chinese population. LEVELS OF EVIDENCE: III.

20.
Sci Total Environ ; 719: 137473, 2020 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-32126407

RESUMO

Cloud condensation nuclei (CCN) play an important role in the formation and evolution of cloud droplets. However, the dataset of global CCN number concentration (NCCN) is still scarce due to the lack of direct CCN measurements, hindering an accurate evaluation of its climate effects. Alternative approaches to determine NCCN have thus been proposed to calculate NCCN based on measurements of other aerosol properties, such as particle number size distribution, bulk aerosol chemical composition and aerosol optical properties. To better understand the interaction between haze pollution and climate, we performed direct CCN measurements in the winter of 2018 at the Gucheng site, a typical polluted suburban site in North China Plain (NCP). The results show that the average CCN concentrations were 3.81 × 103 cm-3, 5.35 × 103 cm-3, 9.74 × 103 cm-3, 1.27 × 104 cm-3, 1.44 × 104 cm-3 at measured supersaturation levels of 0.114%, 0.148%, 0.273%, 0.492% and 0.864%, respectively. Based on these observational data, we have further investigated two methods of calculating NCCN from: (1) bulk aerosol chemical composition and particle number size distribution; (2) bulk aerosol chemical composition and aerosol optical properties. Our results showed that both methods could well reproduce the observed concentration (R2 > 0.88) and variability of NCCN with a 9% to 23% difference in the mean value. Further error analysis shows that the estimated NCCN tends to be underestimated by about 20% during the daytime while overestimated by <10% at night compared with the measured NCCN. These results provide quantitative instructions for the NCCN prediction based on conventional aerosol measurements in the NCP.

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