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1.
Plant Cell Physiol ; 2020 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-32049334

RESUMO

Extracellular ATP (eATP) is an apoplastic signaling molecule that plays essential roles in the growth and development of plants. Arabidopsis seedlings have been reported to respond to eATP, however, the downstream signaling components are still not well understood. Here, we report that an ethylene responsive factor, Redox Responsive Transcription Factor 1 (RRTF1), is involved in eATP-regulated Arabidopsis thaliana seedling growth. Exogenous ATP inhibited green seedling root growth and induced hypocotyl bending of etiolated seedlings. RRTF1 loss-of-function mutant (rrtf1) seedlings showed decreased responses to eATP, while its complementation or overexpression led to recovered or increased eATP responsiveness. RRTF1 was expressed rapidly after eATP stimulation and then migrated into the nuclei of root tip cells. eATP-induced auxin accumulation in root tip or hypocotyl cells was impaired in rrtf1. Chromatin immunoprecipitation (ChIP) and high-throughput sequencing results indicated that eATP induced some genes related to cell growth and development in wild type but not in rrtf1 cells. These results suggest that RRTF1 may be involved in eATP signaling by regulating functional gene expression and cell metabolism in Arabidopsis seedlings.

2.
Adv Mater ; : e1905629, 2020 Feb 13.
Artigo em Inglês | MEDLINE | ID: mdl-32053238

RESUMO

Solid-state batteries enabled by solid-state polymer electrolytes (SPEs) are under active consideration for their promise as cost-effective platforms that simultaneously support high-energy and safe electrochemical energy storage. The limited oxidative stability and poor interfacial charge transport in conventional polymer electrolytes are well known, but difficult challenges must be addressed if high-voltage intercalating cathodes are to be used in such batteries. Here, ether-based electrolytes are in situ polymerized by a ring-opening reaction in the presence of aluminum fluoride (AlF3 ) to create SPEs inside LiNi0.6 Co0.2 Mn0.2 O2 (NCM) || Li batteries that are able to overcome both challenges. AlF3 plays a dual role as a Lewis acid catalyst and for the building of fluoridized cathode-electrolyte interphases, protecting both the electrolyte and aluminum current collector from degradation reactions. The solid-state NCM || Li metal batteries exhibit enhanced specific capacity of 153 mAh g-1 under high areal capacity of 3.0 mAh cm-2 . This work offers an important pathway toward solid-state polymer electrolytes for high-voltage solid-state batteries.

3.
Am J Chin Med ; 48(1): 107-126, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31931593

RESUMO

The Chinese patent medicine She-Xiang-Xin-Tong-Ning (SXXTN) is a clinical medication for coronary heart disease (CHD) and angina pectoris. This study aimed to investigate pharmacological effects of SXXTN and elucidate the role in angiogenesis on human umbilical vein endothelial cells (HUVECs) and acute myocardial ischemia (AMI) rats. We prepared SXXTN to treat the cells to reveal their effects on oxidative stress-damaged cell viability, as well as cell proliferation, migration, and tube formation processes. SXXTN was also used to treat coronary artery ligation-induced acute myocardial ischemia rats to confirm whether it had positive effect on myocardial issues by hematoxylin and eosin (HE), 2,3,5-triphenyltetrazolium chloride (TTC) staining and immunohistochemical staining. We measured the levels of peroxidative damage-related enzymes in cytoplasm and serum by biochemical kits and detected vascular endothelial growth factor (VEGF), angiotensin II (Ang II), thromboxane B2 (TXB2), and 6-keto-prostaglandin F1 alpha (6-keto-PGF1α) levels in cells and rats by enzyme-linked immunosorbent assay (ELISA) kits. The results showed that SXXTN protects HUVECs against oxidative stress damage and reversed the decrease of superoxide dismutase (SOD), glutathione (GSH) and increase of creatine kinase (CK), lactate dehydrogenase (LDH) caused by oxidative stress. SXXTN promoted angiogenesis through stimulating cell migration, tube formation, and activating VEGF/VEGFR2 and ERK1/2 pathways. Furthermore, SXXTN reduced infarct size and inhibited PGI2/TXA2 imbalance, preventing atherosclerosis plaque rupture leading to worsening coronary heart disease. Taken together, we report the first in vivo and in vitro evidence that SXXTN reduced oxidative stress-mediated damage and enhanced angiogenesis, which might be useful in treatment of myocardial infarction.

4.
Nat Chem Biol ; 2020 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-31932723

RESUMO

In plants, lineage-specific metabolites can be created by activities derived from the catalytic promiscuity of ancestral proteins, although examples of recruiting detoxification systems to biosynthetic pathways are scarce. The ubiquitous glyoxalase (GLX) system scavenges the cytotoxic methylglyoxal, in which GLXI isomerizes the α-hydroxy carbonyl in the methylglyoxal-glutathione adduct for subsequent hydrolysis. We show that GLXIs across kingdoms are more promiscuous than recognized previously and can act as aromatases without cofactors. In cotton, a specialized GLXI variant, SPG, has lost its GSH-binding sites and organelle-targeting signal, and evolved to aromatize cyclic sesquiterpenes bearing α-hydroxyketones to synthesize defense compounds in the cytosol. Notably, SPG is able to transform acetylated deoxynivalenol, the prevalent mycotoxin contaminating cereals and foods. We propose that detoxification enzymes are a valuable source of new catalytic functions and SPG, a standalone enzyme catalyzing complex reactions, has potential for toxin degradation, crop engineering and design of novel aromatics.

5.
Artigo em Inglês | MEDLINE | ID: mdl-31971263

RESUMO

PURPOSE: The purpose of this study was to evaluate the roles of the clinical research coordinator (CRC) in clinical oncology trials. DESIGN AND METHODS: An E-questionnaire that includes 10 sections with 155 items total and is based on the Clinical Trials Nursing Questionnaire (CTNQ) was designed to determine the conditions of demographics, competences, activities, and psychology for Chinese CRCs. Eighty-two CRCs from three different provinces in China were invited to join this study anonymously. Cronbach's α and split-half reliability were calculated to assess the reliability and validity of the questionnaire. Additionally, the Wilcoxon rank-sum test was used to find the similarity and difference between the importance of the roles of CRCs and their frequency. The STROBE checklist for observational research has been following for presenting the research (see File S1). FINDINGS: Cronbach's α values of the Chinese version of the questionnaire for the frequency scale and the importance scale were .965 and .961, respectively. The split-half reliability coefficients were 0.866 and 0.805, respectively. Pearson correlation coefficients of the subscales indicated that the correlation between each item and its dimension was greater than its correlation with the other components (P < .05). Exploratory factor analysis results show that three common factors were extracted by principal component analysis and had eigenvalues greater than 1 and that the cumulative contribution rate was 69.415%. PRACTICE IMPLICATIONS: The Chinese version of the questionnaire has good reliability and validity for CRCs in China, which could be promoted in evaluating clinical research coordinator roles in China.

6.
Inorg Chem ; 59(2): 1383-1392, 2020 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-31916435

RESUMO

There is a challenge for noncontact temperature-sensing techniques and the related materials, in which a highly reliable contactless thermometer probe with low cost and high sensitivity is in demand. Here, the Lu3Al5O12:Ce3+/Mn4+ phosphor has been designed and prepared for the high-performance fluorescence temperature-sensing application in a novel one-pot, self-redox, solid-state process. Benefiting from the different electron-lattice/phonon interactions of Ce3+ and Mn4+, two distinguishable emission peaks with significantly different temperature responses originating from Ce3+ and Mn4+ are realized. Applying the fluorescence intensity ratio of Mn4+ versus Ce3+ and the decay lifetime of Mn4+ emission as the temperature readout, a dual-mode optical temperature-sensing mechanism was proposed and studied in the temperature range of 100-350 K. The maximum relative sensitivities (Sr) are derived as 4.37 and 3.22% K-1 respectively, as well as a large chromaticity shift visible to naked eyes (ΔE = 153 × 10-3 in 100-350 K) is observed. This is the first report of a Ce3+,Mn4+ co-doped dual-emitting phosphor, and its unique optical thermometric features demonstrate the high potential of Lu3Al5O12:Ce3+/Mn4+ as an accurate and reliable thermometer probe candidate.

7.
Clin Sci (Lond) ; 134(1): 75-85, 2020 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-31899483

RESUMO

Renalase, a recently discovered secreted flavoprotein, exerts anti-apoptotic and anti-inflammatory effects against renal injury in acute and chronic animal models. However, whether Renalase elicits similar effects in the development of diabetic nephropathy (DN) remains unclear. The studies presented here tested the hypothesis that Renalase may play a key role in the development of DN and may have therapeutic potential for DN. Renalase expression was measured in human kidney biopsies with DN and in kidneys of db/db mice. The role of Renalase in the development of DN was examined using a genetically engineered mouse model: Renalase knockout mice with db/db background. The renoprotective effects of Renalase in DN was evaluated in db/db mice with Renalase overexpression. In addition, the effects of Renalase on high glucose-induced mesangial cells were investigated. Renalase was down-regulated in human diabetic kidneys and in kidneys of db/db mice compared with healthy controls or db/m mice. Renalase homozygous knockout increased arterial blood pressure significantly in db/db mice while heterozygous knockout did not. Renalase heterozygous knockout resulted in elevated albuminuria and increased renal mesangial expansion in db/db mice. Mesangial hypertrophy, renal inflammation, and pathological injury in diabetic Renalase heterozygous knockout mice were significantly exacerbated compared with wild-type littermates. Moreover, Renalase overexpression significantly ameliorated renal injury in db/db mice. Mechanistically, Renalase attenuated high glucose-induced profibrotic gene expression and p21 expression through inhibiting extracellular regulated protein kinases (ERK1/2). The present study suggested that Renalase protected against the progression of DN and might be a novel therapeutic target for the treatment of DN.

8.
J Biol Chem ; 295(6): 1646-1657, 2020 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-31907282

RESUMO

Legionella pneumophila is the causative agent of the lung malady Legionnaires' disease, it modulates host function to create a niche termed the Legionella-containing vacuole (LCV) that permits intracellular L. pneumophila replication. One important aspect of such modulation is the co-option of the host ubiquitin network with a panel of effector proteins. Here, using recombinantly expressed and purified proteins, analytic ultracentrifugation, structural analysis, and computational modeling, along with deubiquitinase (DUB), and bacterial infection assays, we found that the bacterial defective in organelle trafficking/intracellular multiplication effector Ceg23 is a member of the ovarian tumor (OTU) DUB family. We found that Ceg23 displays high specificity toward Lys-63-linked polyubiquitin chains and is localized on the LCV, where it removes ubiquitin moieties from proteins ubiquitinated by the Lys-63-chain type. Analysis of the crystal structure of a Ceg23 variant lacking two putative transmembrane domains at 2.80 Å resolution revealed that despite very limited homology to established members of the OTU family at the primary sequence level, Ceg23 harbors a catalytic motif resembling those associated with typical OTU-type DUBs. ceg23 deletion increased the association of Lys-63-linked polyubiquitin with the bacterial phagosome, indicating that Ceg23 regulates Lys-63-linked ubiquitin signaling on the LCV. In summary, our findings indicate that Ceg23 contributes to the regulation of the association of Lys-63 type polyubiquitin with the Legionella phagosome. Future identification of host substrates targeted by Ceg23 could clarify the roles of these polyubiquitin chains in the intracellular life cycle of L. pneumophila and Ceg23's role in bacterial virulence.

9.
Int J Biol Macromol ; 146: 497-507, 2020 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-31923489

RESUMO

Cyclic GMP-AMP (cGAMP) synthase (cGAS) is a predominant DNA sensor inducing the activation of the innate immune responses that produce proinflammatory cytokines and type I interferons, which has been well-investigated in mammals. However, chicken cGAS (chcGAS), which participates in avian innate immunity, has not been well-investigated. Here, we cloned the complete open reading frame sequence of chcGAS. Multiple sequence alignment and phylogenetic analysis revealed that chcGAS was homologous to mammalian cGAS. The chcGAS mRNA was highly expressed in the bone marrow and ileum. The subcellular localization of chcGAS was mainly in the cytoplasm, and partial co-localization was observed in the endoplasmic reticulum. Through overexpression and RNA interference, we demonstrated that chcGAS responded to exogenous dsDNA, HS-DNA, and poly(dA:dT), and to self dsDNA from the DNA damage response, thereby triggering the activation of STING/TBK1/IRF7-mediated innate immunity in both chicken embryonic fibroblasts and chicken liver cancer cells. Furthermore, downregulation of chcGAS enhanced the infection of fowl adenovirus serotype 4 in LMH cells. Our results demonstrated that chcGAS was an important cytosolic DNA sensor activating innate immune responses and may shed light on a strategy for preventing infectious diseases in the poultry industry.

10.
Infect Genet Evol ; 80: 104173, 2020 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-31917357

RESUMO

The phylum Acanthocephala is a small group of endoparasites occurring in the alimentary canal of all major lineages of vertebrates worldwide. In the present study, the complete mitochondrial (mt) genome of Cavisoma magnum (Southwell, 1927) (Palaeacanthocephala: Echinorhynchida) was determined and annotated, the representative of the family Cavisomidae with the characterization of the complete mt genome firstly decoded. The mt genome of this acanthocephalan is 13,594 bp in length, containing 36 genes plus two non-coding regions. The positions of trnV and SNCR (short non-coding region) in the mt genome of C. magnum are different comparing to those of the other acanthocephalan species available in GenBank. Phylogenetic analysis based on amino acid sequences of 12 protein-coding genes using Bayesian inference (BI) supported the class Palaeacanthocephala and its included order Polymorphida to be monophyletic, but rejected monophyly of the order Echinorhynchida. Our phylogenetic results also challenged the validity of the genus Sphaerirostris (Polymorphida: Centrorhynchidae). The novel mt genomic data of C. magnum are very useful for understanding the evolutionary history of this group of parasites and establishing a natural classification of Acanthocephala.

11.
Life Sci ; 244: 117343, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-31978449

RESUMO

AIMS: Epithelial-mesenchymal transition (EMT) is one of the important regulators of metastasis in advanced hepatocellular carcinoma (HCC). Blocking the Notch signaling pathway and then reversing the EMT process is a hot spot in clinical tumor research. Here, we aimed to investigate the effect and underlying mechanisms of ADAM-17 (a key cleavage enzyme of Notch pathway) inhibitor ZLDI-8 we found before on the metastasis of hepatocellular carcinoma in vitro and in vivo. MAIN METHODS: The cell viability of HCC cells was evaluated by MTT and colony formation assays. Migration and invasion were assessed respectively with wound healing and transwell assays. The expression and location of proteins were detected by western blot and immunofluorescence, respectively. The effects of ZLDI-8 on metastasis of liver cancer in vivo were investigated in a tail vein injection model. KEY FINDINGS: In the present work, ZLDI-8 significantly inhibited proliferation, migration, invasion and EMT phenotype of highly aggressive MHCC97-H and LM3 cells. Moreover, ZLDI-8 could inhibit the migration and invasion of HepG2 and Bel7402 cells induced by TGF-ß1. ZLDI-8 suppressed the protein expression of interstitial markers and increased that of epithelial markers. Meanwhile, ZLDI-8 decreased the expression of proteins in the Notch signaling pathway. Finally, ZLDI-8 blocks metastasis in the lung metastasis model in vivo. SIGNIFICANCE: ZLDI-8 suppressed the metastasis of hepatocellular carcinoma, which was associated with reversing the EMT process and regulating Notch signaling pathway. The study laid the foundation for the discovery of drugs that reverse EMT to inhibit advanced HCC metastasis.

12.
Chem Commun (Camb) ; 56(10): 1489-1492, 2020 Feb 04.
Artigo em Inglês | MEDLINE | ID: mdl-31960845

RESUMO

The construction of active sites with excellent water oxidation activity is of great significance in the design of OER electrocatalysts. Herein, we propose an anion regulation strategy, in which N-doped carbon nanotubes play a protective role by coating the Ni3Fe alloy particles and two non-metallic elements S and Se are introduced to adjust the electronic structure, this can further help construct a heterogeneous surface, improve the valence state, and increase the hydrophilicity of the catalysts. The two as-prepared catalysts N-CNTs@NiS2/Fe7S8 (overpotential of 330 mV to achieve 50 mA cm-2 and Tafel slope of 51.49 mV dec-1) and N-CNTs@NiSe2/Fe3Se4 (360 mV and 72.32 mV dec-1, respectively) exhibited considerably high OER activity in 1.0 M KOH solutions.

13.
J Biol Chem ; 2020 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-31949049

RESUMO

Insulin secretion by pancreatic islet ß-cells is regulated by glucose levels and is accompanied by proton generation. The voltage-gated proton channel Hv1 is present in pancreatic ß-cells and extremely selective for protons. However, whether Hv1 is involved in insulin secretion is unclear. Here, we demonstrate that Hv1 promotes insulin secretion of pancreatic ß-cells and glucose homeostasis. Hv1-deficient mice displayed hyperglycemia and glucose intolerance due to reduced insulin secretion, but retained normal peripheral insulin sensitivity. Moreover, Hv1 loss contributed much more to severe glucose intolerance as the mice got older. The islets of Hv1-deficient and heterozygous mice were markedly deficient in glucose- and K+-induced insulin secretion. In perifusion assays, Hv1 deletion dramatically reduced both the first and second phase of glucose-stimulated insulin secretion (GSIS). Islet insulin and proinsulin contents were reduced, and histological analysis of pancreas slices revealed an accompanying modest reduction of ß-cell mass in the Hv1-knockout mice. EM observations also indicated a reduction in insulin granule size, but not granule number or granule docking, in the Hv1-deficient mice. Mechanistically, Hv1 loss limited the capacity of glucose-induced membrane depolarization, accompanying the reduced ability of glucose to raise Ca2+ levels in islets, evidenced by a decreased duration of individual calcium oscillations. Moreover, Hv1 expression was significantly reduced in pancreatic ß-cells from streptozotocin-induced diabetic mice, indicating that Hv1 deficiency is associated with ß-cell dysfunction and diabetes. We conclude that Hv1 regulates insulin secretion and glucose homeostasis through a mechanism that depends on intracellular Ca2+ levels and membrane depolarization.

14.
Nanotechnology ; 2020 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-31952059

RESUMO

We present a systematic study on the effects of CF4 plasma immersion ion implantation (PIII) in Si on the phase evolution of ultra-thin Ni silicides. For 3 nm Ni, NiSi2 was formed on Si substrates with and without CF4 PIII at temperature as low as 400℃. For 6 nm Ni, NiSi was formed on pure Si, while epitaxial NiSi2 was obtained on CF4 PIII Si. The incorporation of C and F atoms in the thin epitaxial NiSi2 significantly reduces the layer resistivity. Increasing the Ni thickness to 8 nm results in the formation of NiSi, where the thermal stability of NiSi, the NiSi/Si interface and Schottky contacts are significantly improved with CF4 PIII. We suggest that the interface energy is lowered by the F and C dopants presenting in the layer and at the interface, leading to phase evolution of the thin Ni silicide.

15.
J Am Chem Soc ; 142(3): 1341-1347, 2020 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-31893500

RESUMO

Active oxygen species (AOS) play key roles in many important catalytic reactions relevant to clean energy and environment. However, it remains challenging to characterize the active sites for producing AOS and to image the surface properties of AOS, especially on multicomponent metallic catalyst surfaces. Herein, we utilize tip-enhanced Raman spectroscopy (TERS) to probe the local generation and diffusion of OH radicals on a Pd/Au(111) bimetallic catalyst surface. The reactive OH radicals can be catalytically generated from hydrogen peroxide (H2O2) at the metal surface, which then oxidizes the surface adsorbed thiolate, a reactant that is used as the TERS probe. By TERS imaging of the spatial distribution of unreacted thiolate molecules, we demonstrate that the Pd surface is active for generation of OH radicals and the Pd step edge shows much higher activity than the Pd terrace, whereas the Au surface is inactive. Furthermore, we find that the locally generated OH radicals at the Pd step edge could diffuse to both the Au and the Pd surface sites to induce oxidative reactions, with a diffusion length estimated to be about 5.4 nm. Our TERS imaging with few-nanometer spatial resolution not only unravels the active sites but also characterizes in real space the diffusion behavior of OH radicals. The results are highly valuable to understand AOS-triggered catalytic reactions. The strategy of using reactants with large Raman cross sections as TERS probes may broaden the application of TERS for studying catalysis with reactive small molecules.

16.
Ying Yong Sheng Tai Xue Bao ; 31(1): 333-339, 2020 Jan.
Artigo em Chinês | MEDLINE | ID: mdl-31957412

RESUMO

A large amount of azo dye wastewater is discharged into the environment, with serious risks to ecosystems and human health. Therefore, the development of treatment technology of azo dye wastewater was of practical significance. Photocatalytic methods showed promising application prospects due to easy to implement and effective. In this study, layered black phosphorus nanosheet (LBP) was used as a catalyst through liquid phase exfoliation method. Methyl orange (MO) was employed as a model azo dye to investigate the catalytic mechanism of LBP. The dominant transient species involved in the photocatalytic reaction was probed by quenching and fluorescence probe experiments. Degradation pathways of MO were proposed according to degradation products identified by the liquid chromatography-mass spectrometry. The results showed that degradation rate (kobs) of MO at acidic condition (pH=3.0) or alkaline condition (pH=11.0) was higher than that at neutral condition (pH=7.0). Degradation pathways of MO included that the azo bond was attacked by hydroxyl radicals (·OH) photogenerated by the LBP, and the intermediate products were further oxidized by ·OH to produce N, N-dimethyl-4-(2-p-phenylmethylhydrazine) aniline, 2-(dimethylamino)-5-((4(dimethylamino) phenyl) diazenyl) phenol and N, N-dimethyl-4-nitroaniline.


Assuntos
Ecossistema , Fósforo , Compostos Azo , Águas Residuárias
17.
Am J Orthod Dentofacial Orthop ; 157(1): 105-116, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31901268

RESUMO

This case report describes the successful extraction treatment of a Class II malocclusion with excessive maxillary sinus pneumatization. A 20-year-old man sought treatment with the major complaint of protrusive mouth and anterior teeth. He was diagnosed with a skeletal Class II relationship and protrusion of the maxilla. The clinical examination showed a severe Class II molar relationship with excessive overjet and deep overbite. Panoramic radiograph showed obvious maxillary sinus pneumatization bilaterally. Three premolars and one deciduous molar were extracted, and spaces were used to correct molar relationship and retract maxillary incisors. Light forces and low speed movement were applied to overcome the challenge of moving teeth through the maxillary sinus wall. Balanced facial esthetic and stable occlusion were obtained posttreatment with a notable bone formation of the maxillary sinus wall. This result highlights the possibility of tooth movement through cortical floor with bone remodeling and no obvious complications.


Assuntos
Má Oclusão de Angle Classe II , Sobremordida , Cefalometria , Humanos , Masculino , Seio Maxilar , Técnicas de Movimentação Dentária , Adulto Jovem
18.
J Agric Food Chem ; 68(4): 1101-1109, 2020 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-31904947

RESUMO

ε-Poly-l-lysine (ε-PL) consists of 25-35 lysine residues which are linked by an isopeptide bond formed by dehydration condensation of α-carboxyl and ε-amino groups and has good antibacterial activity and broad-spectrum inhibition range. However, there is no clear conclusion about the structure and antibacterial mechanism of ε-PL in aqueous solution. Herein, a high purity of ε-PL was prepared using Amberlite IRC-50 ion-exchange resin. Membrane filtration and dynamic light scattering were used to study the variations of ε-PL aggregation in aqueous solution with pH value. The conformational changes and antibacterial activities of ε-PL and carbamoylated ε-PL in different water environments were studied with circular dichroism (CD) and inhibition zone. The structural changes during the spray-drying process were determined by Fourier transform infrared spectroscopy. The results indicated that the side chain amino charge played a decisive role in the ε-PL conformation and aggregation. ε-PL exhibited the properties of a ß-sheet during spray drying from acidic liquids to solids. The cation enhanced the antibacterial activity of ε-PL but did not play a key role. Instead, the backbone of ε-PL might determine the mechanism of ε-PL antibacterial.

19.
Chem Commun (Camb) ; 2020 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-31976495

RESUMO

A general method for the synthesis of structurally diverse N-arylpyrazoles from readily available cyclopropanols and aryldiazonium salts is disclosed. The reaction was conducted at room temperature within minutes with a broad substrate scope and excellent regioselectivity.

20.
Artigo em Inglês | MEDLINE | ID: mdl-31984615

RESUMO

Comprehensive investigation of inter-functional coordination between OER and ORR takes on the important action of designing highly active and durable bifunctional oxygen catalysts. Here, we highlight redox-inert Zn2+ in spinel-type oxide (ZnXNi1-XCo2O4) to synergistically optimize physical pore structure and increase the formation of active species on the surface of catalyst. The presence of Zn2+ segregation has been identified experimentally and theoretically under oxygen-evolving condition, the newly formed VZn-O-Co allows more suitable binding interaction between the active center Co and the oxygenated species, resulting in superior ORR performance. Moreover, a liquid flow Zn-air battery is constituted employing the structurally optimized Zn0.4Ni0.6Co2O4 nanoparticles supported on N-doped carbon nanotube (ZNCO/NCNTs) as an efficient air cathode, which presents remarkable power density (109.1 mW cm-2), high open circuit potential (1.48 V vs. Zn), excellent durability and high-rate performance. This finding could elucidate the experimentally observed enhancement in the ORR activity of ZnXNi1-XCo2O4 oxides after the OER test. The atomic-level insight into the new catalyst activation strategy based on Zn vacancies is adaptable for developing dual-functional Zn-contained spinel electrocatalysts.

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