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1.
J Am Chem Soc ; 2020 May 18.
Artigo em Inglês | MEDLINE | ID: mdl-32372644

RESUMO

The quinoid structure, a resonance structure of benzenoid, gives rise to peculiar chemical reactivity and physical properties. A complete characterization of its geometric and electronic properties on the atomic scale is of vital importance to understand and engineer the chemical and physical properties of quinoid molecules. Here, we report a real-space structural and electronic characterization of quinoid poly(para-phenylene) (PPP) chains by using noncontact atomic force microscopy and scanning tunneling microscopy. Our results reveal that quinoid PPP chains adopt a coplanar adsorption configuration on Cu(111) and host in-gap states near Fermi level. In addition, intra- and interchain hopping of quinoid structure are observed, indicative of a quasiparticle behavior originating from charge-lattice interactions. The experimental results are nicely reproduced by tight-binding calculations. Our study provides a comprehensive understanding of the structural and electronic properties of quinoid PPP chains in real space and may be further extended to address the dynamics of nonlinear excitations in quinoid molecules.

2.
J Vis Exp ; (159)2020 May 04.
Artigo em Inglês | MEDLINE | ID: mdl-32421006

RESUMO

Prolonged exposure to high concentrations of oxygen leads to inflammation and acute lung injury, which is similar to human bronchopulmonary dysplasia (BPD). In premature infants, BPD is a major complication despite early use of surfactant therapy, optimal ventilation strategies, and noninvasive positive pressure ventilation. Because pulmonary inflammation plays a crucial role in the pathogenesis of BPD, corticosteroid use is one potential treatment to prevent it. Nevertheless, systemic corticosteroid treatment is not usually recommended for preterm infants due to long-term adverse effects. Preclinical studies and human phase I clinical trials demonstrated that use of mesenchymal stromal cells (MSCs) in hyperoxia-induced lung injuries and in preterm infants is safe and feasible. Intratracheal and intravenous MSC transplantation has been shown to protect against neonatal hyperoxic lung injury. Therefore, intratracheal administration of stem cells and combined surfactant and glucocorticoid treatment has emerged as a new strategy to treat newborns with respiratory disorders. The developmental stage of rat lungs at birth is equivalent to that in human lungs at 26-28 week of gestation. Hence, newborn rats are appropriate for studying intratracheal administration to preterm infants with respiratory distress to evaluate its efficacy. This intratracheal instillation technique is a clinically viable option for delivery of stem cells and drugs into the lungs.

3.
Artigo em Inglês | MEDLINE | ID: mdl-32398475

RESUMO

Obesity induced cardiomyopathy involves chronic and sustained inflammation. Toll-like receptor 4 (TLR4) signaling pathway can associate innate immunity with obesity. Myeloid differentiation primary response 88 (MyD88), an indispensable down-stream adaptor molecule of TLR4, has been reported to mediate obesity complications. However, whether inhibition of MyD88 can mitigate obesity-induced heart injury remains unclear. LM8, a new MyD88 inhibitor, exhibits prominent anti-inflammatory activity in LPS treated macrophages. In the present study, the protective effects of LM8 on high fat diet (HFD)-induced heart injury were assessed in a mouse model of obesity. As suggested from the achieved results, LM8 treatment alleviated HFD-induced pathological and functional damage of heart in mice. Meantime, the treatment of mice with LM8 could significantly inhibit myocardial hypertrophy, fibrosis, inflammatory cytokines expression, as well as inflammatory cells infiltration induced by HFD. Besides, LM8 administration inhibited the formation of MyD88/TLR4, phosphorylation of ERK and activation of NF-κB induced by HFD. According to the achieved results, MyD88 inhibitor LM8 ameliorated obesity-induced heart injury by inhibiting MyD88-ERK/NF-κB dependent cardiac inflammatory pathways. Furthermore, targeting MyD88 might be a candidate of therapeutic method to treat obesity-induced heart injury.

4.
Cancer Sci ; 2020 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-32437084

RESUMO

Cancer is one of the primary causes of human mortality worldwide despite persistent efforts and developments. No independent life on earth can live without iron whereas some species can without oxygen. Iron provides us with a double-edged sword. Excess iron is a risk for carcinogenesis whilst its deficiency causes anemia leading to oxygen shortage. Every cell is eventually destined to death, which has been classified either into apoptosis or necrosis by morphology. According with the scientific advancements, regulated necrosis has been recognized by distinct forms. Ferroptosis is defined as catalytic Fe(II)-dependent regulated necrosis accompanied by lipid peroxidation. The premiere observation was necrosis of fibrosarcoma cells by inhibiting cystine/glutamate antiporter with erastin, which reduced intracellular cysteine, thus glutathione, levels. Our current understanding of ferroptosis is relative abundance of iron (catalytic Fe[II]) in comparison to sulfur (sulfhydryls). Thus, either excess iron or sulfur deficiency causes ferroptosis. Cell proliferation inevitably requires iron for DNA synthesis and energy production. Carcinogenesis is a process toward iron addiction with ferroptosis-resistance. Conversely, ferroptosis is associated with aging and neurodegeneration. Ferroptosis of immune cells during infection is advantageous for infectious agents, whereas ferroptosis-resistance incubates carcinogenic soil as excess iron. Cancer cells are rich in catalytic Fe(II). Directing established cancer cells to ferroptosis is a novel strategy to discover new cancer therapies. Appropriate iron regulation would be a tactics to reduce and delay carcinogenesis.

5.
Food Chem ; 321: 126712, 2020 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-32247179

RESUMO

Zein, a class of prolamine proteins extracted from maize, is extensively used in the food and pharmaceutical industries. Characterization of its components is essential for quality control and safety evaluation. We performed in silico digestion of zein proteins using tandem combinations of different proteinases, to improve protein sequence coverage and subsequent identification by nano-LC-MS/MS analysis. Trypsin/chymotrypsin yielded the highest protein sequence coverage of up to 79.5% and increased the number of proteins from 11 to 35 compared to trypsin/Lys-C. Besides, SDS-PAGE analysis revealed 37 proteins in the zein extract, as well as the possibility of protein polymers. Also, 420 peptides originating from 71 proteins were identified, of which 116 were predicted as bioactive by in silico approach. In conclusion, in silico prediction coupled with multi-enzyme digestion can significantly improve the coverage of complex zein protein proteome, and the potential function of zein proteins and peptides need be further investigated.

6.
Artigo em Inglês | MEDLINE | ID: mdl-32344848

RESUMO

Understanding water intake variation is crucial for assessing human exposure to water pollutants. The correlation between water intake and demographic factors warrants further exploration. A cross-sectional study was conducted to estimate urban water consumption and its associated factors among adults in Wuxi, China, in 2015. The water consumption information was obtained by a 24-h self-report diary over seven consecutive days. A classification and regression tree (CART) analysis was applied to detect how water consumption varied with the demographic variables. Finally, a total of 1188 adults (18-87 years old) were included. The results demonstrated that the median water consumption of the adults was 1525 mL/day in summer and 1217 mL/day in winter. The results of the CART analysis demonstrated that body mass index (BMI) and age were the leading factors that were associated with water consumption in summer and winter, respectively. The water consumption threshold of BMI for men differed from women (23 kg/m2 vs. 18 kg/m2) in summer, and the threshold of age for men was also different from women (43 years vs. 21 years) in winter. In conclusion, the findings are useful for accurately assessing human exposure to water pollutants and identifying the high-risk subgroups.

7.
Zhongguo Shi Yan Xue Ye Xue Za Zhi ; 28(2): 500-506, 2020 Apr.
Artigo em Chinês | MEDLINE | ID: mdl-32319386

RESUMO

OBJECTIVE: To investigate the clinical characteristics and prognostic factors of children with non-Hodgkin's lymphoma of different pathological subtypes. METHODS: Ninety-three patients with newly-diagnosed childhood NHL in Fujian Medical University Union Hospital from March 2011 to September 2017 were salected. The diagnosis of patients was performed according to the World Health Organization classification of tumors 2008 ys. The chemotherapy regimens were based on immune phenotype, pathological type and clinical stages. The 5-years event-free survival rate (EFS) were calculated and analyzed by Kaplan-Meier method, and difference of survival rate between groups were compared. The possible factors influencing 5-years EFS was analyzed using Cox proportional hazards model. RESULTS: Among the 93 patients, male to female ratio was 2.88:1, the median age at diagnosis was 6 (0.9 to 13) years old. According to pathological types, Burkitt's lymphoma was the most common, follow by ALK+ anaplastic large-cell lymphoma (ALCL) and lymphoblastic lymphoma (LBL). Clinically, the most common initial symptoms observed at diagnosis were swelling of superficial lymph node, and abdominal pain and abdominal mass in mature B-cell neoplasms, and the swelling of mediastinal lymph nodes in LBL, and hemophagocytic syndrome (HPS) in mature T-cell and natural killer cell NHL. Seventy-nine cases completed 2 courses of induction chemotherapy, and 64 cases (81.01%) reached complete remission (CR). In a median follow up for 32.5(1.0-88.5) months, ten patients (11.90%) relapsed, the median relapsed time was 5.7(3.4-15.7) months. 5-year EFS rate in 84 patients received standardized treatments were (77.1±4.9)%. As compared with lymphoblastic lymphoma and extranodal NK/T cell lymphoma, there was a trend towards better outcomes in B-LBL, and mature B-cell neoplasms and ALK+ ALCL showing 5-year EFS was (86.2±5.2)% and (93.8±6.1)% vs (53.3%±16.1)% and (28.6±17.1)%. Univariate analysis showed that B symptoms, LDH level, secondary HLH, immunophenotype, pathological subtypes, clinical stage and whether reached CR after induction chemotherapy significantly correlated with prognosis. Cox regression analysis showed that no CR after 2 courses was an independent unfavorable prognostic factor (HR0.001, 95%CI: 0.000-0.122). CONCLUSION: The clinical characteristics and prognosis of patients with NHL of different pathological types are different. Whether reached CR after induction chemotherapy is the imdependent risk factor affecting the prognosis.

8.
J Org Chem ; 85(9): 6216-6224, 2020 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-32270678

RESUMO

A chemoselective and diastereoselective synthesis of fused oxazolidines was achieved by a three-component cascade reaction of tetrahydroisoquinolines (THIQs), α,ß-unsaturated aldehydes, and diethyl 2-oxomalonate. Probably due to the reactivity difference between the aldehyde and the ketone, the reaction proceeded through the condensation of THIQs with α,ß-unsaturated aldehydes and 1,3-dipolar cycloaddition of the generated azomethine ylide intermediate with 2-oxomalonate. The key features are easily available starting materials, mild reaction conditions, broad substrate scope, and high chemo- and diastereoselectivity.

9.
Org Lett ; 2020 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-32275450

RESUMO

Through the oxidative addition of cobalt into the N-C(O) bond of phthalimide and the subsequent decarbonylation, we describe an efficient cobalt-catalyzed intermolecular decarbonylative carboamidation of alkynes. High regioselectivities have been achieved for unsymmetrical alkynes (including aryl-alkyl or aryl-aryl) to deliver polysubstituted isoquinolones. To facilitate step economy, a three-component decarbonylative carboamidation of alkynes with phthalic anhydrides and amines has been demonstrated using the current cobalt catalysis.

10.
Cardiovasc Ther ; 2020: 3568608, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32256707

RESUMO

Children with Kawasaki disease (KD) resistant to intravenous immunoglobulin (IVIG) have a higher incidence of coronary artery lesions (CAL). Despite the association between Purinergic receptor P2Y12 (P2RY12) polymorphism, KD genetic susceptibility, and CAL complications being proved, few studies have assessed the relationship between P2RY12 polymorphisms and IVIG resistance in patients with KD. We recruited 148 KD patients with IVIG resistance and 611 with IVIG sensitivity and selected five P2RY12 polymorphisms: rs9859538, rs1491974, rs7637803, rs6809699, and rs2046934. A significant difference in the genotype distributions between patients was only observed for the rs6809699 A > C polymorphism (AC vs. AA: adjusted odds ratio (OR) = 0.48, 95% confidence interval (CI) = 0.27-0.84, P=0.011; AC/CC vs. AA: adjusted OR = 0.47, 95% CI = 0.27-0.83, P=0.0084). After adjusting for age and gender, the carriers of the rs6809699 C allele had OR of 0.44 to 0.49 for IVIG sensitivity (AC vs. AA: adjusted OR = 0.48, 95% confidence interval (CI) = 0.27-0.84, P=0.011; AC/CC vs. AA: adjusted OR = 0.47, 95% CI = 0.27-0.83, P=0.0084) compared to the carriers of a rs6809699 AA genotype, suggesting the protective effect of this SNP against IVIG resistance. Moreover, individuals with all five protective polymorphisms experienced a significantly decreased IVIG resistance compared to that of individuals with up to three protective polymorphisms (adjusted OR = 0.27, 95% CI = 0.13-0.57, P=0.0006). Our results suggest that the P2RY12 rs6809699 polymorphism could be used as a biomarker to predict IVIG resistance in KD patients.

11.
Cell Mol Biol Lett ; 25: 26, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32308692

RESUMO

Background: Oxidative stress results in cell apoptosis/death and plays a detrimental role in disease development and progression. Stressors alter the miRNA expression profile and miRNAs play a role in the cell response to stress. We previously showed that miR-711 is significantly over-expressed in extended cold ischemia reperfusion injured hearts in heart transplant. In this study, we aimed to investigate the role of miR-711 in cardiac cell damage in response to oxidative stress and how miR-711 is regulated. Methods: Rat cardiac cell line H9c2 cells were cultured and exposed to oxidative conditions (Antimycin A (AA), H2O2, CoCl2, or cold hypoxia/reoxygenation (H/R)) in vitro. H9c2 cells were transfected with miR-711 mimics, miR-711 inhibitors, or small interference RNA, using transfection reagents. The expression of miR-711 was measured by quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR). Cell apoptosis/death was detected by flow cytometry and an IncuCyte system. Mitochondrial damage was detected by measuring the mitochondria membrane potential by flow cytometry. Gene expression was detected by qRT-PCR at the mRNA level and Western blotting and immunocytochemistry staining at the protein level. Results: We found that miR-711 was significantly up-regulated in cells treated with H2O2, AA, CoCl2, and cold H/R. Over-expression of miR-711 increased cell apoptosis/death induced by AA and H/R whereas cell death was reduced by miR-711 inhibitors. MiR-711 induced cell death through negative regulation of angiopoietin 1 (Ang-1), fibroblast growth factor 14 (FGF14) and calcium voltage-gated channel subunit alpha1C (Cacna1c) genes. Both knockdown of hypoxia inducible factor 1α (HIF-1α) and inactivation of the nuclear factor kappa-light-chain-enhancer of activated B cells (NFКB) pathway inhibited over-expression of miR-711. Conclusion: Oxidative stress increases the expression of miR-711. Over-expression of miR-711 induces cell apoptosis/death. HIF-1α and NFКB regulate miR-711 in H9c2 cells during oxidative stress. miR-711 is a new target for preventing oxidative stress.

12.
Nanotechnology ; 31(30): 305708, 2020 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-32259801

RESUMO

Low dimensional superconductors have many unusual properties. When 0-dimensional superconductors reach the nanometer scale, the superconducting energy gap can be enhanced due to the shell effect. At the same time, the single electron Coulomb blockade effect can also be observed on metal nanoparticles if they are weakly coupled to the environment. So, if a superconducting nanoparticle is isolated well from the environment, the superconducting gap and the Coulomb gap would couple together, making the tunneling spectrum more complicated and interesting. Here Sn nanoparticles were deposited on the surface of STO (111). The charging energy of a nanoparticle mainly depends on its size and is comparable to the superconducting gap when the isolated particle is large enough. The superconducting energy gap can be deduced from the coupling tunneling spectrum and the shell effect is observed. The method to deduce the superconducting gap here is simpler than when fit using the Dynes density of states. Owing to the increased superconducting gap and critical field, the studied nanoparticles may find applications in studies of the properties of Majorana fermions.

13.
Virol J ; 17(1): 46, 2020 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-32245493

RESUMO

BACKGROUND: Porcine epidemic diarrhea virus (PEDV) infection causes an acute enteric tract infectious disease characterized by vomiting, anorexia, dehydration, weight loss and high mortality in neonatal piglets. During PEDV infection, the spike protein (S) is a major virion structural protein interacting with receptors and inducing neutralizing antibodies. However, the neutralizing B-cell epitopes within PEDV S protein have not been well studied. METHODS: To accurately identify the important immunodominant region of S1, the purified truncated S1 proteins (SA, SB, SC, SD and SE) were used to immunize BALB/c mice to prepare polyclonal antibodies. The antisera titers were determined by indirect ELISA, western blot and IFA after four immunizations to find the important immunodominant region of S1, and then purified the immunodominant region of S1 protein and immunized mice to generate the special antibodies, and then used recombinant peptides to determine the B-cell epitopes of monoclonal antibodies. RESULTS: Five antisera of recombinant proteins of the spike protein region of PEDV were generated and we found that only the polyclonal antibody against part of the S1 region (signed as SE protein, residues 666-789) could recognize the native PEDV. Purified SE protein was used to immunize BALB/c mice and generate mAb 2E10. Pepscan of the SE protein demonstrated that SE16 (722SSTFNSTREL731) is the minimal linear epitope required for reactivity with the mAb 2E10. Further investigation indicated that the epitope SE16 was localized on the surface of PEDV S protein in the 3D structure. CONCLUSIONS: A mAb 2E10 that is specifically bound to PEDV was generated and identified a specific linear B-cell epitope (SE16, 722SSTFNSTREL731) of the mAb. The epitope region of PEDV S1 localized in the different regions in comparison with the earlier identified epitopes. These findings enhance the understanding of the PEDV spike protein structure for vaccine design and provide a potential use for developing diagnostic methods to detect PEDV.

14.
Toxins (Basel) ; 12(3)2020 Mar 23.
Artigo em Inglês | MEDLINE | ID: mdl-32210020

RESUMO

Exposure to aflatoxin is considered to be one of the causes of hepatocellular carcinoma (HCC). With the development of bioinformation, we sought to reveal the occurrence and development of aflatoxin-induced HCC through data research. We identified differentially expressed genes (DEGs) of datasets GSE127791 (Aflatoxin-treated pluripotent stem cell derived human hepatocytes vs. controls) and GSE64041 (liver carcinoma with unknown cause vs. non-cancerous tissue) by GEO2R to find the common DEGs. Gene ontology (GO) and KEGG path enrichment analysis were used to annotate the function of DEGs. Hub genes were screened from identified DEGs by protein-protein interaction (PPI) network analysis. The prognostic value of hub genes in cancer databases were evaluated. We obtained 132 common DEGs and 11 hub genes. According to cluster analysis and protein co-expression networks, we screened out the key genes, histidine-rich glycoprotein (HRG) and phosphoenolpyruvate carboxykinase 2 (PCK2). Oncomine database and survival curve analysis showed that the decline in HRG and PCK2 expression in the development of HCC indicated poor prognosis. We speculated that the decreased expression of HRG and PCK2 after aflatoxin exposure to hepatocyte may be related to aflatoxin induced hepatocyte injury and carcinogenesis. In addition, the decreased expression of HRG and PCK2 in the occurrence and development of HCC suggests a poor prognosis of HCC.

15.
Environ Sci Technol ; 54(10): 6202-6212, 2020 May 19.
Artigo em Inglês | MEDLINE | ID: mdl-32207945

RESUMO

Microplastics (MPs) have caused increasing global concerns due to their detrimental effects on marine ecosystems. However, the role of photodegradation in altering toxicity of MPs to marine organisms is poorly understood. We therefore investigated the photolytic transformation of pristine polystyrene fragments (P-PS) by 60-day ultraviolet (UV) irradiation, and compared the toxicity of P-PS, photodegraded PS (PD-PS), and commercially available polystyrene microbeads (C-PS) to juvenile grouper (Epinephelus moara). Photodegradation reduced the size from ∼55.9 µm of P-PS to ∼38.6 µm of PD-PS, even produced nanoparticles (∼75 nm) with a yield of 7.03 ± 0.37% (w/w), and induced surface oxidation and formation of persistent free radicals (e.g., CO•, COO•). Also, endogenous pollutants (chemical additives and polymer fragments) were leached out. Thus, PD-PS had the highest growth inhibition and lipidosis-driven hepatic lesions of grouper, followed by P-PS and C-PS, which was mainly explained by increased hepatic bioaccumulation of MPs/NPs and released endogenous toxicants. Furthermore, oxidative stress-triggered mitochondrial depolarization, suppression of fatty acid oxidation and transport, and promotion of inflammation were identified as the key mechanisms for the enhanced hepatotoxicity after photodegradation. This work provides new insight into the potential hazard and harm of MPs in marine environments after photodegradation.

16.
Environ Sci Technol ; 54(7): 3840-3848, 2020 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-32119780

RESUMO

Condensation fine particles (CFPs) from coal-fired flue gas harm humans and the environment after being emitted into the atmosphere. Given their small size (<0.1 µm), difficulty arises in efficiently removing CFPs by wet electrostatic precipitators and mist eliminators. In this work, a laboratory apparatus was used to study the CFP growth under simulated power plant conditions. Four methods were independently investigated to increase the particle size: addition of ammonia, addition of fly ash, decreasing temperature, and applying an electrical discharge. Results demonstrated that the CFP size distribution possessed a unimodal structure with peak at 0.05 µm. At increased ammonia concentration from 10 to 30 ppm, the peak of growth factor shifted rightward and increased from 1.21 to 1.35 and the range of growth factor >1 was significantly broadened due to joint action of multiple mechanisms. Fly ash acted as the core, and CFPs adhered to the ash surface when forming ash-salt droplets. Cooling flue gas could also enhance the CFP growth due to vapor condensation. At decreased temperature from 45 to 30 °C, the median diameter of CFPs increased by 15%. Finally, the growth and agglomeration of CFPs can be further enhanced when an external electrical field was utilized. The size range of growth factor >1 can be broadened, and the peak growth factor significantly increased at 8 kV applied voltage. The research findings provide valuable guidance for effectively improving the CFP removal efficiency by external regulation for growth enhancement.

17.
BMC Public Health ; 20(1): 286, 2020 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-32131783

RESUMO

BACKGROUND: Dehydration due to insufficient fluid intake (IFI) is detrimental to health. This cross-sectional study aimed to assess the fluid intake of urban adults in Wuxi, China, and to identify potential risk factors contributing to IFI. METHODS: Adults were selected from the urban area of Wuxi, China, using a multiple-stage random sampling method. The fluid intake information was obtained with a 24-h self-reported diary over seven consecutive days in both summer and winter of 2015. A classification and regression tree (CART) analysis was conducted to detect the potential risk factors associated with IFI. CART is a machine-learning algorithm that portions the data into subsets by threshold. RESULTS: A total of 584 adults aged 18-87 years were included. The results showed that the median (P25-P75) values of daily fluid intake of the participants were 1100 (800-1550) mL in summer and 1000 (750-1300) mL in winter. Women had a higher prevalence of IFI than men in both summer (odds ratio (OR) = 2.683, 95% confidence interval (CI): 1.830-3.934) and winter (OR = 2.636, 95% CI: 1.677-4.142). The results of CART analysis showed that, in summer, BMI < 25 kg/m2 (probability: 64.2%) and age < 64 years (probability: 67.4%) were main risk factors of IFI for men, and BMI < 29 kg/m2 (probability: 81.6%) and living in C Community (probability: 86.7%) were main risk factors for women. In winter, age < 40 years (probability: 81.8%) and BMI < 20 kg/m2 (probability: 94.5%) were identified as main risk factors of IFI for men and women, respectively. CONCLUSIONS: Most of the participants living in the study site had IFI. The fluid consumption varied by gender, age, location, and BMI. The findings could be useful for the implementation and optimization of intervention programs by identifying the individuals who may at greater risk of dehydration.

18.
Chem Commun (Camb) ; 56(20): 2983-2986, 2020 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-32091053

RESUMO

Chirality-induced recognition-promoted molecule-level self-sorting assembly in a two-component supramolecular gel system constructed by two polyhedral oligomeric silsesquioxane (POSS) core-based dendritic gelators with similar geometry and peripheral functionality, which would normally form a homogeneous co-assembled network.

19.
Artigo em Inglês | MEDLINE | ID: mdl-32100523

RESUMO

Substantial progress has been made in the experimental synthesis of large-area two-dimensional transition metal dichalcogenide (TMD) thin films in recent years. This has provided a solid basis to build non-planar structures to implement the unique electrical and mechanical properties of TMDs in various nanoelectronic and mechano-electric devices, which, however, has not yet been fully explored. In this work, we demonstrate the fabrication and characterization of MoS2 field-effect transistors (FETs) with an omega (Ω)-shaped gate. The FET is built based on the SiO2/MoS2 core-shell heterostructure integrated using atomic layer deposition (ALD) technique. The MoS2 thin film has been uniformly deposited by ALD as wrapping the SiO2 nanowire forming the channel region, which is further surrounded by the gate dielectric and the Ω-gate. The device has exhibited n-type behavior with effective switching comparable to the reference device with a planar MoS2 channel built on a SiO2/Si substrate. Our work opens up an attractive avenue to realize novel device structures utilizing synthetic TMDs, thereby broadening their potential application in future advanced nanoelectronics.

20.
Environ Sci Technol ; 54(5): 3022-3031, 2020 03 03.
Artigo em Inglês | MEDLINE | ID: mdl-32045525

RESUMO

Sulfuric acid aerosol (SAA) can considerably deteriorate air visibility, which poses a threat to human health. Pretreatment methods that enlarge SAA sizes are crucial to enhanced emission control from industrials. This study provides an insight into SAA growth in terms of aerosol dynamics simulation and growth experiments under simulated flue gas conditions. Results show that SAA growth dynamics are dominated by coagulation and condensation mechanisms for small and large aerosols, respectively. The two mechanisms are coupled mainly in SAA sizes smaller than 0.05 µm. A large amount of time was allotted for the SAA distribution to grow into an approximately log-normal form without the use of any activation methods. Cooling gas and corona discharge can both enhance SAA growth. Cooling gas is in charge of condensation, whereas corona discharge mainly acts on coagulation. They exhibited 14.3% and 12.3% increases in mean diameter and 12.3% and 69.1% decreases in number concentration. In contrast, adding vapor led to a 1.58% decrease in mean diameter and a 9.4% increase in number concentration. Findings suggest that combining cooling gas and corona discharge to simultaneously promote coagulation and condensation and reduce SAA emission from humid flue gas is possible.


Assuntos
Poluentes Atmosféricos , Aerossóis , Gases , Humanos , Tamanho da Partícula , Ácidos Sulfúricos
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