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1.
Bioinformatics ; 2021 Oct 08.
Artigo em Inglês | MEDLINE | ID: mdl-34623423

RESUMO

MOTIVATION: Recent advancements in fluorescence in situ hybridization (FISH) techniques enable them to concurrently obtain information on the location and gene expression of single cells. A key question in the initial analysis of such spatial transcriptomics data is the assignment of cell types. To date, most studies used methods that only rely on the expression levels of the genes in each cell for such assignments. To fully utilize the data and to improve the ability to identify novel sub-types we developed a new method, FICT, which combines both expression and neighborhood information when assigning cell types. RESULTS: FICT optimizes a probabilistic function that we formalize and for which we provide learning and inference algorithms. We used FICT to analyze both simulated and several real spatial transcriptomics data. As we show, FICT can accurately identify cell types and sub-types improving on expression only methods and other methods proposed for clustering spatial transcriptomics data. Some of the spatial subtypes identified by FICT provide novel hypotheses about the new functions for excitatory and inhibitory neurons. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics FICT is available at: https://github.com/haotianteng/FICT.

2.
Sci Total Environ ; : 150868, 2021 Oct 06.
Artigo em Inglês | MEDLINE | ID: mdl-34626623

RESUMO

Land degradation has become one of the most critical environmental and socioeconomic issues in the world, particularly in Central Asia. Moreover, the realization of Land Degradation Neutrality (LDN) in Central Asia faces enormous challenges in achieving the global Sustainable Development Goal 15.3 (SDG 15.3). It is critical to monitor land degradation and assess its drivers in Central Asia. In this study, an Optimal Land Degradation Index (OLDI) was established as a new index for monitoring land degradation using a constrained optimization algorithm. The spatiotemporal characteristics of LDN were monitored in Central Asia. Further analysis explored the driving force of land degradation in different areas. The results showed that 7.22% and 15.33% of the total land area exhibited land improvement and land degradation, respectively. According to abrupt change analysis, mutation changes in the OLDI were observed in 2005, 2012 and 2015. At the subnational scale, most regions in Central Asia have not achieved the goal of LDN. The residual analysis highlighted the drivers of spatial differences in land degradation performance in Central Asia. Drought was the main driving force affecting land degradation by the compound effect of decreased precipitation and increased temperature on the Ustyurt Plateau, while 24.01% of the land degradation areas resulted from anthropogenic disturbances and were mainly distributed in the areas surrounding the Aral Sea. The results also indicated that 72.56% of the land improvement areas resulted from human activities and were mainly concentrated in the Balkhash Lake Delta and the Amudarya Delta. In Central Asia, the realization of SDG 15.3 by 2030 remains a severe challenge. Restoration measures should be prioritized in land degradation areas in Central Asia to implement the LDN initiative, especially around the Aral Sea.

3.
Spectrochim Acta A Mol Biomol Spectrosc ; 266: 120419, 2021 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-34619506

RESUMO

Nitroaromatic compounds (NACs) can lead to various environmental pollution healh problems. In order to effectively recognize and sense NACs, a novel coordination polymers (CPs) with fluorescent characteristic [Zn3(btc)2(tpt)(H2O)2]·4H2O (1) (tpt = tris(4-pyridyl)triazine, H3btc = 1,3,5-benzenetricarboxylic acid) has been triumphantly prepared as an fluorescence probe by solvothermal method. 1 possesses remarkable PH stability ranging from 2.0 to 12.0 and is also stable in different pure organic solvents. It should be noted that 1 manifests a fluorescence quenching response against the detection of selectivity and sensitivity towards 2,4,6-trinitrophenol (TNP) in aqueous solution. It also makes analysis on the limit of detection towards TNP, which is as low as 0.94 µM compared with most reported CPs sensors for TNP. Therefore, 1 can become a satisfactory sensor for TNP detection with remarkable selectivity, strong anti-interference and favorable recyclability. In addition, the quenching mechanisms were also discussed. It was supposed that the mechanisms of photoinduced electron transfer (PET) as well as resonance energy transfer (RET) might be the main influencing factors.

4.
Acta Pharmacol Sin ; 2021 Sep 22.
Artigo em Inglês | MEDLINE | ID: mdl-34552216

RESUMO

Despite improvements in cardiovascular disease (CVD) outcomes by cholesterol-lowering statin therapy, the high rate of CVD is still a great concern worldwide. Dehydrocorydaline (DHC) is an alkaloidal compound isolated from the traditional Chinese herb Corydalis yanhusuo. Emerging evidence shows that DHC has anti-inflammatory and antithrombotic benefits, but whether DHC exerts any antiatherosclerotic effects remains unclear. Our study revealed that intraperitoneal (i.p.) injection of DHC in apolipoprotein E-deficient (ApoE-/-) mice not only inhibited atherosclerosis development but also improved aortic compliance and increased plaque stability. In addition, DHC attenuated systemic and vascular inflammation in ApoE-/- mice. As macrophage inflammation plays an essential role in the pathogenesis of atherosclerosis, we next examined the direct effects of DHC on bone marrow-derived macrophages (BMDMs) in vitro. Our RNA-seq data revealed that DHC dramatically decreased the levels of proinflammatory gene clusters. We verified that DHC significantly downregulated proinflammatory interleukin (IL)-1ß and IL-18 mRNA levels in a time- and concentration-dependent manner. Furthermore, DHC decreased lipopolysaccharide (LPS)-induced inflammation in BMDMs, as evidenced by the reduced protein levels of CD80, iNOS, NLRP3, IL-1ß, and IL-18. Importantly, DHC attenuated LPS-induced activation of p65 and the extracellular signal-regulated kinase 1/2 (ERK1/2) pathway. Thus, we conclude that DHC ameliorates atherosclerosis in ApoE-/- mice by inhibiting inflammation, likely by targeting macrophage p65- and ERK1/2-mediated pathways.

5.
Environ Res ; 204(Pt B): 112051, 2021 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-34529971

RESUMO

Anammox has been widely used for the treatment of nitrogen wastewater. However, the problem of stable NO2- supplement becomes one of the limiting factors. It is an effective method to obtain NO2- by denitrifying the NO3-, including the by-product of Anammox. In this study, NO2- was reinforced by bio-electrochemical system (BES) through the reaction of partial denitrification in situ in an Anammox reactor. Our results showed that both NO3- and NO2- can be reduced on the cathode with different Coulombic efficiencies. The reduction of NO3- amount increased with an increase in Inf-NO3-, which was greater than that of NO2-. The conversion amount of NO3- was 2.50% ± 17.25% to the theoretical Eff-NO3-, and the maximum reduction amount was 23.24% with the highest Coulombic efficiency of 3.56%. High throughput results showed that denitrifying bacteria, such as Limnobacter, Thauera, Denitratisoma, Nitrosomonas and Nitrospira, were attached to the cathode surface and in Anammox granular sludge. This study showed that NO2- can be supplied by reducing the by-product NO3- with denitrification cathode at Anammox environment in-situ.

6.
J Colloid Interface Sci ; 607(Pt 1): 229-241, 2021 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-34500422

RESUMO

Distant metastases and chemotherapy repellency are the key causes of colorectal cancer (CRC)-related mortality. Regorafenib, an oral multi-kinase inhibitor approved for treating advanced CRC with distant metastases and/or chemo-resistance, however only improves median overall survival by 1.4 months. Such limited therapeutic effect is likely due to the low bioavailability of orally administered hydrophobic regorafenib. A regorafenib nanodrug is fabricated by one-step self-assembly with a clinically often-used fluorescent agent (indocyanine green) for overcoming regorafenib's limitations, towards improving regorafenib's therapeutic efficacy in advanced CRC. This nanodrug (nanoRF) was characterized, and its antitumor effects were assessed in three preclinical CRC models. NanoRF converts regorafenib's delivery approach from oral to intravenous with a significantly high encapsulation efficacy of regorafenib (96%) and a long-time colloidal stability. Nanodrug (nanoRF) markedly prolongs regorafenib's blood circulation by halving clearance rate, and enhances regorafenib's tumor accumulation. Across three preclinical CRC models (xenografted tumor, chemodrug-resistant xenografted tumor, and liver metastasis), nanoRF drastically enhances regorafenib's tumor inhibiting efficacy by 0.5-4 folds and effectively extends survival by 0.5-5 folds. This regorafenib nanodrug is a simple, safe, and efficient therapeutic nanodrug for treating advanced CRC with a ready-to-be-clinically-translated potential.

7.
Adv Sci (Weinh) ; : e2102854, 2021 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-34541830

RESUMO

Dispersing inorganic colloidal nanoparticles within nematic liquid crystals provides a versatile platform both for forming new soft matter phases and for predefining physical behavior through mesoscale molecular-colloidal self-organization. However, owing to formation of particle-induced singular defects and complex elasticity-mediated interactions, this approach has been implemented mainly just for colloidal nanorods and nanoplatelets, limiting its potential technological utility. Here, orientationally ordered nematic colloidal dispersions are reported of pentagonal gold bipyramids that exhibit narrow but controlled polarization-dependent surface plasmon resonance spectra and facile electric switching. Bipyramids tend to orient with their C5 rotation symmetry axes along the nematic director, exhibiting spatially homogeneous density within aligned samples. Topological solitons, like heliknotons, allow for spatial reorganization of these nanoparticles according to elastic free energy density within their micrometer-scale structures. With the nanoparticle orientations slaved to the nematic director and being switched by low voltages ≈1 V within a fraction of a second, these plasmonic composite materials are of interest for technological uses like color filters and plasmonic polarizers, as well as may lead to the development of unusual nematic phases, like pentatic liquid crystals.

8.
J Hazard Mater ; 416: 125815, 2021 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-34492781

RESUMO

In this study, seven laccase genes from different bacteria were linked with the signal peptides PelB, Lpp or Ompa for heterologous expression in E. coli. The recombinant strains were applied for the removal of sulfadiazine (SDZ), sulfamethazine (SMZ), and sulfamethoxazole (SMX). The results obtained for different signal peptides did not provide insights into the removal mechanism. The removal ratios of SDZ, SMZ, and SMX obtained with the recombinant strain 6#P at 60 h were around 92.0%, 89.0%, and 88.0%, respectively. The degradation pathways of sulfonamides have been proposed, including SO2 elimination, hydroxylation, oxidation, pyrimidine ring cleavage, and N-S bond cleavage. Different mediators participate in the degradation of antibiotics through different mechanisms, and different antibiotics have different responses to the same mediator. The addition of 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) slightly promoted the removal of sulfonamides by most recombinant strains with different signal peptides, especially for the recombinant strain 2#O. The removal of sulfonamides by 1-hydroxybenzotriazole (HBT) varied with the recombinant strains. Syringaldehyde (SA) had a slight inhibitory effect on the removal of sulfonamides, with the most significant effect on strains 7#L and 7#O.


Assuntos
Antibacterianos , Lacase , Bactérias , Escherichia coli/genética , Lacase/genética , Sulfonamidas
9.
Acta Biomater ; 2021 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-34496281

RESUMO

Multidrug resistance (MDR) is a major cause accounting for chemotherapy failure and recurrence of malignant tumors. A prominent mechanism underlying MDR is overexpression of P-glycoprotein (P-gp, a drug efflux pump). Promoting drug delivery efficacy by targeting tumor and concurrently suppressing drug efflux through down-regulating P-gp emerges as an effective strategy to enhance intracellular drug accumulation for combating MDR tumor. General Control Non-repressed 5 (GCN5), a histone acetyltransferase acting as an epigenetic regulator of multidrug resistance protein 1 (MDR1), positively regulates P-gp levels in drug-resistant cancer cells. Herein, a hyaluronic acid-coated, pH/redox dual-responsive nanosystem (HPMSNs) is fabricated for co-delivering doxorubicin (DOX) and GCN5 siRNA (siGCN5). This nanosystem can effectively encapsulate DOX and siRNA preventing premature leakage and releasing these therapeutics intracellularly via its pH/redox dual responsiveness. Through CD44-mediated targeting, DOX/siGCN5@HPMSNs increases drug internalization in CD44-overexpressing cancer cells, and markedly promotes DOX retention by down-regulating P-gp expression in drug-resistant cancers through silencing GCN5. Of note, in an MDR breast tumor model, DOX and siGCN5 co-delivered HPMSNs inhibits MDR tumor growth by 77%, abolishes P-gp-mediated drug resistance, and eliminates DOX's systemic toxicity. Thus, the tumor-targeting, stimuli-responsive nanosystem is an effective carrier for co-delivering anticancer drug and siRNA for combating cancer drug resistance. STATEMENT OF SIGNIFICANCE: We designed a tumor-targeting, pH/redox dual-responsive nanosystem (HPMSNs) for chemo-drug and siRNA co-delivery. This nanosystem efficiently co-delivered DOX and siGCN5 into drug-resistant cancer cells and significantly inhibited the tumor growth through: (1) HA shell enhanced the cellular internalization of loaded DOX and siGCN5 via CD44-mediated targeting; (2) the pH/redox dual-responsive nanosystem released the cargos in response to the intracellular environment; (3) the released siGCN5 downregulated P-gp epigenetically. In an MDR breast tumor model (MCF7/ADR), DOX and siGCN5 loaded HPMSNs markedly inhibited tumor growth, almost completely abolished P-gp expression, and minimized systemic toxicity of DOX.

10.
IEEE Trans Image Process ; 30: 7702-7716, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34478366

RESUMO

Superpixels are widely used in computer vision applications. Most of the existing superpixel methods use established criteria to indiscriminately process all pixels, resulting in superpixel boundary adherence and regularity being unnecessarily inter-inhibitive. This study builds upon a previous work by proposing a new segmentation strategy that classifies image content into meaningful areas containing object boundaries and meaningless parts that include color-homogeneous and texture-rich regions. Based on this classification, we design two distinct criteria to process the pixels in different environments to achieve highly accurate superpixels in content-meaningful areas and keep the regularity of the superpixels in content-meaningless regions. Additionally, we add a group of weights when adopting the color feature, successfully reducing the undersegmentation error. The superior accuracy and the moderate compactness achieved by the proposed method in comparative experiments with several state-of-the-art methods indicate that the content-adaptive criteria efficiently reduce the compromise between boundary adherence and compactness.

11.
Molecules ; 26(17)2021 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-34500694

RESUMO

Nitrogen-rich porous networks with additional polarity and basicity may serve as effective adsorbents for the Lewis electron pairing of iodine molecules. Herein a carbazole-functionalized porous aromatic framework (PAF) was synthesized through a Sonogashira-Hagihara cross-coupling polymerization of 1,3,5-triethynylbenzene and 2,7-dibromocarbazole building monomers. The resulting solid with a high nitrogen content incorporated the Lewis electron pairing effect into a π-conjugated nano-cavity, leading to an ultrahigh binding capability for iodine molecules. The iodine uptake per specific surface area was ~8 mg m-2 which achieved the highest level among all reported I2 adsorbents, surpassing that of the pure biphenyl-based PAF sample by ca. 30 times. Our study illustrated a new possibility for introducing electron-rich building units into the design and synthesis of porous adsorbents for effective capture and removal of volatile iodine from nuclear waste and leakage.

12.
J R Soc Interface ; 18(182): 20210413, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34493091

RESUMO

Synthetic gene networks are frequently conceptualized and visualized as static graphs. This view of biological programming stands in stark contrast to the transient nature of biomolecular interaction, which is frequently enacted by labile molecules that are often unmeasured. Thus, the network topology and dynamics of synthetic gene networks can be difficult to verify in vivo or in vitro, due to the presence of unmeasured biological states. Here we introduce the dynamical structure function as a new mesoscopic, data-driven class of models to describe gene networks with incomplete measurements of state dynamics. We develop a network reconstruction algorithm and a code base for reconstructing the dynamical structure function from data, to enable discovery and visualization of graphical relationships in a genetic circuit diagram as time-dependent functions rather than static, unknown weights. We prove a theorem, showing that dynamical structure functions can provide a data-driven estimate of the size of crosstalk fluctuations from an idealized model. We illustrate this idea with numerical examples. Finally, we show how data-driven estimation of dynamical structure functions can explain failure modes in two experimentally implemented genetic circuits, a previously reported in vitro genetic circuit and a new E. coli-based transcriptional event detector.

13.
Sci Total Environ ; 801: 149748, 2021 Aug 18.
Artigo em Inglês | MEDLINE | ID: mdl-34467905

RESUMO

Physical and chemical treatments of Tungsten smelting wastewater, with high salt content and low C/N ratio, are often tedious. As a solution, this study suggested a simultaneous nitrification and denitrification membrane bioreactor (SND-MBR) for salinity gradient domestication. During the salinity acclimation period, we observed 20% and 11% removal of NH4+-N and Chemical Oxygen Demand (COD), respectively. However, the SND efficiency reached 95.55% after stable operation at 3.0% salinity. Through stoichiometric and kinetic analyses, we confirmed that increased salinity significantly inhibited electron transport system activity, nitrification, and denitrification, evidenced by the extremely low ammonia monooxygenase and nitrite reductase activities. Further high-throughput sequencing showed that Nitrosomonas dominated the functional microbial flora succession and denitrification in high salinity environments. In comparison with a control, the Kyoto Encyclopedia of Genes and Genomes analysis showed that wastewater salinity weakened the functional gene level of MBR microbial flora, and the enzyme key to the assimilation nitrate reduction changed from nitrate reductase to assimilation nitrate reductase.

14.
J Am Chem Soc ; 2021 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-34482686

RESUMO

High-speed capturing of uranyl (UO22+) ions from seawater elicits unprecedented interest for the sustainable development of the nuclear energy industry. However, the ultralow concentration (∼3.3 µg L-1) of uranium element leads to the slow ion diffusion inside the adsorbent particle, especially after the transfer paths are occupied by the coexisted interfering ions. Considering the geometric dimension of UO22+ ion (a maximum length of 6.04-6.84 Å), the interlayer spacing of graphene sheets was covalently pillared with phenyl-based units into twice the ionic length (13 Å) to obtain uranyl-specific nanofluidic channels. Applying a negative potential (-1.3 V), such a charge-governed region facilitates a unipolar ionic transport, where cations are greatly accelerated and co-ions are repelled. Notably, the resulting adsorbent gives the highest adsorption velocity among all reported materials. The adsorption capacity measured after 56 days of exposure in natural seawater is evaluated to be ∼16 mg g-1. This novel concept with rapid adsorption, high capacity, and facile operating process shows great promise to implement in real-world uranium extraction.

15.
J Environ Manage ; 301: 113768, 2021 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-34583282

RESUMO

Many studies have assessed the relative sensitivity of ecosystems to climate change, and even optimized climate states from long-term averages to infer short-term changes, but how ecosystem sensitivity and its relationships with climate variability vary over time remains elusive. By combining the vegetation sensitivity index (VSI) and a 15 year moving window, we analyzed interannual variability in spatiotemporal patterns of vegetation sensitivity to short-term climate variability and its correlations with climatic factors in China over the past three decades (1982-2015). We demonstrated that vegetation sensitivity shows high spatial heterogeneity, and varies with vegetation type and climate region. Generally, vegetation in the southwest and mountainous regions was more sensitive, especially coniferous forests and isolated shrubland patches. Comparatively, vegetation in dry regions was less sensitive to climate variability than in wetter climates. Due to frequent climate variability in the early 1990s, a large increase in the VSI was detected in 1996. Significant increases in the interannual variability of vegetation sensitivity were observed in greater than 23.7% of vegetated areas and decreases in only 4.2%. Solar radiation was the dominant climate driver of vegetation sensitivity, followed by temperature and precipitation. However, climate controls are not invariable across a range of climatic conditions, such as precipitation exerted an increasing influence on changes of vegetation sensitivity. Quantitative analyses of ecosystem sensitivity to climate variability such as ours are vital to identify which regions and vegetation are most vulnerable to future climate variability.

16.
Spectrochim Acta A Mol Biomol Spectrosc ; 264: 120276, 2021 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-34455379

RESUMO

A new Lanthanum-based luminescent metal-organic framework, {[La(H2O)4(HL)]·H2O} (1), has been successfully synthesized by employing 3,3',5,5'-azodioxybenzenetetracarboxylic acid (H4L) as a rigid organic linker through the solvothermal reactions. 1 exhibits a two-dimensional (2D) layered structure and a three-dimensional (3D) supramolecular structure is formed by hydrogen bonds between the layers. Stability studies indicate that 1 has good chemical stability and thermostability. Meanwhile, the Ksv values for TNP is 4.61 × 104 M-1 with the LOD of 4.13 × 10-6 M and the Ksv value for Fe3+ is 1.22 × 104 M-1 with the LOD of 1.72 × 10-5 M, respectively, which demonstrated that 1 exhibits high sensitivity and excellent selectivity for the detection of TNP and Fe3+via fluorescence quenching. Significantly, 1 shows high regenerability after five recycling progress for sensing Fe3+. The possible mechanisms associated with the luminescent quenching are discussed in detail through some relevant experiments and tests, as well as the DFT calculations. Based on the above excellent properties of 1, it will have extremely potential to be used as a dual functional sensor for both detecting TNP and Fe3+ in aqueous solution, simultaneously.

17.
J Environ Manage ; 298: 113330, 2021 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-34371215

RESUMO

The dramatic climate change has far-reaching impacts on vegetation in drylands such as Central Asia. Recent attempts to assess vegetation stability to short-term climate variability often account solely for vegetation sensitivity or resilience but ignore the composite effects of these two indicators. Meanwhile, our understanding of the vegetation stability at the seasonal scale remains insufficient. In this study, considering the cumulative effects of vegetation response to three key climate factors, we assessed the stability of vegetation in Central Asia using normalized difference vegetation index (NDVI) and the meteorological data from 1982 to 2014 by integrating vegetation sensitivity and resilience, and further identified the critical regions and seasons of vegetation that experience high risks of pending change. The results show that the sensitivity of vegetation has a strong correlation (R2 = 0.83, p < 0.001) with the aridity index (AI), with the vegetation of drier areas having lower sensitivities to climate variability. At the temporal scale, the sensitivity of vegetation to climate variability varied among different seasons. The average vegetation sensitivity index (VSI) is 41.17, 33.32 and 28.63 in spring, summer and autumn, respectively. Spatially, a trade-off between vegetation sensitivity and resilience is found both for the growing season (R2 = 0.67) and seasonal scale (R2 = 0.71, 0.32 and 0.43 for spring, summer and autumn, respectively), regions with high vegetation sensitivity were always accompanied by strong resilience. Based on the relationship between vegetation sensitivity and resilience, we further identify the critical regions and periods of vegetation with high change risk in Central Asia. Results suggest that herbaceous plants in semi-arid areas present high instability, especially in summer. This study offers a comprehensive perspective to assess vegetation stability to climate variability and the results will facilitate the protection of ecosystems and the implementation of sustainable development goals in Central Asia.


Assuntos
Mudança Climática , Ecossistema , Ásia , Plantas , Estações do Ano , Temperatura
18.
J Org Chem ; 86(18): 12988-13000, 2021 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-34459187

RESUMO

Pd-catalyzed hydroaminocarbonylation (HAC) of alkenes with CO and NH4Cl enables atom-economic and regiodivergent synthesis of primary amides, but the origin of regioselectivity was incorrectly interpreted in previous computational studies. A density functional theory study was performed herein to investigate the mechanism. Different from the previous proposals, both alkene insertion and aminolysis were found to be potential regioselectivity-determining stages. In the alkene insertion stage, 2,1-insertion is generally faster than 1,2-insertion irrespective of neutral or cationic pathways for both P(tBu)3 and xantphos. Such selectivity results from the unconventional proton-like hydrogen of the Pd-H bond in alkene insertion transition states. For less bulky alkenes, aminolysis with P(tBu)3 shows low selectivity, while linear selectivity dominates in this stage with xantphos due to a stronger repulsion between xantphos and branched acyl ligands. It was further revealed that the less-mentioned CO concentration and solvents also influence the regioselectivity by adjusting the relative feasibilities of CO-involved steps and NH3 release from ammonium chloride, respectively. The presented double-regiodetermining-stages mechanistic model associated with the effects of ligands, CO concentration, and solvents well reproduced the experimental selectivity to prove its validity and illuminated new perspectives for the regioselectivity control of HAC reactions.

19.
Dalton Trans ; 50(32): 11249-11258, 2021 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-34341816

RESUMO

Promoting the separation of photogenerated electron-hole pairs and enhancing the charge carrier transfer are critical in photocatalysis. In our work, a ball-flower-like NiS/Zn3In2S6/g-C3N4 photocatalyst fabricated by a hydrothermal method exhibited superior performance for photocatalytic water splitting. The optimized 2.0% NiS/Zn3In2S6/g-C3N4 rivaled noble metal based Pt/g-C3N4 and showed an apparent quantum efficiency (AQE) of 24.3% at 420 nm, with a H2 yield of 4.135 mmol g-1 h-1, which was 30.4 and 9.51 times that of pure g-C3N4 and binary Zn3In2S6/g-C3N4 composites, respectively. The experimental and characterization results suggested that the heterojunction formed between Zn3In2S6/g-C3N4 and the decorating NiS co-catalyst cooperatively suppressed the electron-hole recombination and facilitated the charge carrier transfer, thus resulting in significant improvement of the H2 evolution performance. Moreover, the increased specific surface area and the enhanced visible-light absorption also contributed to superior water splitting performance. The prepared ternary catalytic system with the heterojunction and non-noble metal co-catalyst has great potential as an alternative to noble metals for achieving cost-efficient water splitting systems.

20.
In Vitro Cell Dev Biol Anim ; 57(7): 726-734, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34462813

RESUMO

An efficient and simple method to obtain aortic media for primary culture of rat vascular smooth muscle cells (RVSMCs) is developed. The main steps to obtain aortic media include isolation of rat aortic artery, removal of the fat tissue and branches, separation of longitudinal cutting edge, and peeling off the adventitia. Then, aortic media was used to obtain RVSMCs by our tissue explants method and the enzyme digestion method. The removal efficiency of the intima and adventitia was confirmed by hematoxylin-eosin and immunohistochemical staining. Morphology and immunofluorescent staining were used to identify cells and cell purity. RVSMCs at the 3rd and 8th passages were isolated by our tissue explants method; the enzyme digestion method and the traditional tissue explants method were compared respectively. Western blotting and gel contraction assay were used to investigate the phenotype and contraction ability of RVSMCs obtained by the different methods. Compared with the other methods, RVSMCs isolated by our method showed higher purity and demonstrated "contractile" phenotype with retained contraction ability for more passages. And the aortic media obtained showed no visible damage with few endothelial cells and fibroblasts remained. An efficient and simple method was established to obtain rat aortic media for primary culture of RVSMCs with high purity, "contractile" phenotype characteristics, and more stable during subculturing.

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