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1.
J Comput Chem ; 2024 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-38847556

RESUMO

Herein, we present a density functional theory with dispersion correction (DFT-D) calculations that focus on the intercalation of ionic liquids (ILs) electrolytes into the two-dimensional (2D) Ti3C2Tx MXenes. These ILs include the cation 1-ethyl-3-methylimidazolium (Emim+), accompanied by three distinct anions: bis(trifluoromethylsulfonyl)imide (TFSA-), (fluorosulfonyl)imide (FSA-) and fluorosulfonyl(trifluoromethanesulfonyl)imide (FTFSA-). By altering the surface termination elements, we explore the intricate geometries of IL intercalation in neutral, negative, and positive pore systems. Accurate estimation of charge transfer is achieved through five population analysis models, such as Hirshfeld, Hirshfeld-I, DDEC6 (density derived electrostatic and chemical), Bader, and VDD (voronoi deformation density) charges. In this work, we recommend the DDEC6 and Hirshfeld-I charge models, as they offer moderate values and exhibit reasonable trends. The investigation, aimed at visualizing non-covalent interactions, elucidates the role of cation-MXene and anion-MXene interactions in governing the intercalation phenomenon of ionic liquids within MXenes. The magnitude of this role depends on two factors: the specific arrangement of the cation, and the nature of the anionic species involved in the process.

2.
Immunology ; 168(4): 580-596, 2023 04.
Artigo em Inglês | MEDLINE | ID: mdl-36221236

RESUMO

Hypoxia-induced pulmonary hypertension (HPH) is a progressive and lethal disease characterized by the uncontrolled proliferation of pulmonary artery smooth muscle cells (PASMCs) and obstructive vascular remodelling. Previous research demonstrated that Breg cells were involved in the pathogenesis of pulmonary hypertension. This work aimed to evaluate the regulatory function of Breg cells in HPH. HPH mice model were established and induced by exposing to chronic hypoxia for 21 days. Mice with HPH were treated with anti-CD22 or adoptive transferred of Breg cells. The coculture systems of Breg cells with CD4+ T cells and Breg cells with PASMCs in vitro were constructed. Lung pathology was evaluated by HE staining and immunofluorescence staining. The frequencies of Breg cells, Tfh cells and Tfr cells were analysed by flow cytometry. Serum IL-21 and IL-10 levels were determined by ELISA. Protein levels of Blimp-1, Bcl-6 and CTLA-4 were determined by western blot and RT-PCR. Proliferation rate of PASMCs was measured by EdU. Compared to the control group, mean PAP, RV/(LV + S) ratio, WA% and WT% were significantly increased in the model group. Anti-CD22 exacerbated abnormal hemodynamics, pulmonary vascular remodelling and right ventricle hypertrophy in HPH, which ameliorated by adoptive transfer of Breg cells into HPH mice. The proportion of Breg cells on day 7 induced by chronic hypoxia was significantly higher than control group, which significantly decreased on day 14 and day 21. The percentage of Tfh cells was significantly increased, while percentage of Tfr cells was significantly decreased in HPH than those of control group. Anti-CD22 treatment increased the percentage of Tfh cells and decreased the percentage of Tfr cells in HPH mice. However, Breg cells restrained the Tfh cells differentiation and expanded Tfr cells differentiation in vivo and in vitro. Additionally, Breg cells inhibited the proliferation of PASMCs under hypoxic condition in vitro. Collectively, these findings suggested that Breg cells may be a new therapeutic target for modulating the Tfh/Tfr immune balance in HPH.


Assuntos
Linfócitos B Reguladores , Hipertensão Pulmonar , Ratos , Camundongos , Animais , Hipertensão Pulmonar/etiologia , Linfócitos B Reguladores/metabolismo , Ratos Sprague-Dawley , Células T Auxiliares Foliculares/metabolismo , Remodelação Vascular/fisiologia , Pulmão/patologia , Hipóxia/complicações , Hipóxia/metabolismo , Proliferação de Células
3.
Int J Biometeorol ; 65(2): 235-246, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33118114

RESUMO

This study was conducted to assess the link of miRNA expressions in cow's mammary gland undergoing heat stress. Twelve Holstein cows were allocated either to undergo heat stress (HS) or remain in a thermoneutral environment (non-heat stress, NS), respectively. The experiment with HS cows was carried out in August, and the experiment with NS cows was done in November. After a month, three cows from each group were slaughtered, and mammary gland samples were obtained, and then miRNA were extracted from the samples for later sequencing. From the miRNA-seq, we obtained a total of 124 differentially expressed miRNAs in HS and NS cows' mammary gland. The differentially expressed miRNA could be predicted to influence multiple target genes. The target interleukin-1 (IL-1), which play a role in regulating the function of mammary gland in dairy cows, could be affected by bta-let-7c, bta-let-7e, bta-miR-181d, bta-miR-452, and bta-miR-31. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis showed that mitogen-activated protein kinase (MAPK) pathway plays an important role in the mammary glands of dairy cows and bta-miR-25 and bta-miR-382 may influence MAPK pathway through c-Jun N-terminal kinase (JNK) gene to affect the function of mammary gland in HS cows. In conclusion, this study characterized expression profile of miRNAs in the Holstein cows' mammary gland under summer heat stress or not. We observed miRNA expression during heat stress, which was significantly different from non-heat stress states. A comprehensive analysis of the miRNA's expression will be helpful to further study the link of miRNAs with mechanisms regulating heat stress in the cow mammary gland.


Assuntos
Transtornos de Estresse por Calor , MicroRNAs , Animais , Bovinos/genética , Feminino , Perfilação da Expressão Gênica , Transtornos de Estresse por Calor/genética , Transtornos de Estresse por Calor/veterinária , Resposta ao Choque Térmico/genética , MicroRNAs/genética , Estações do Ano
4.
Phys Chem Chem Phys ; 20(22): 15168-15173, 2018 Jun 06.
Artigo em Inglês | MEDLINE | ID: mdl-29789817

RESUMO

Deep eutectic solvents (DESs) based on 1-ethyl-3-methylimidazolium chloride (EmimCl) and triethylene glycol (TEG) with different molar ratios (from 6 : 1 to 1 : 1) were prepared. FTIR and theoretical calculation indicated that the C2-H on the imidazolium ring form hydrogen bonds with the hydroxyl group rather than the ether O atom of the TEG. The EmimCl-TEG DESs can efficiently capture SO2; in particular, EmimCl-TEG (6 : 1) can capture 0.54 g SO2 per gram of solvent at 0.10 atm and 20 °C, the highest absorption amount for DESs under the same conditions. Theoretical calculation showed that the high SO2 absorption capacity was mainly due to the strong charge-transfer interaction between SO2 and the anion Cl-. Moreover, SO2 desorption in the DESs can be controlled by tuning the interaction between EmimCl and TEG, and the DESs can be cycled many times.

5.
J Phys Chem A ; 120(30): 6089-102, 2016 Aug 04.
Artigo em Inglês | MEDLINE | ID: mdl-27428048

RESUMO

In this work, the interactions between imidazolium-based ionic liquids and some stable radicals based on 2,2,6,6-tetramethylpiperidine-1-yloxyl (TEMPO) have been systematically investigated using density functional theory calculations at the level of M06-2x. Several different substitutions, such as hydrogen bonding formation substituent (OH) and ionic substituents (N(CH3)3(+) and OSO3(-)), are presented at the 4-position of the spin probe, which leads to additional hydrogen bonds or ionic interactions between these substitutions and ionic liquids. The interactions in the systems of the radicals containing ionic substitutions with ionic liquids are predicted much stronger than those in the systems of neutral radicals, resulting in a significant reduction of the mobility of ionic radicals in ionic liquids. To further understand the nature of these interactions, the natural bond order, atoms in molecules, noncovalent interaction index, electron density difference, energy decomposition analysis, and charge decomposition analysis schemes were employed. The additional ionic interactions between ionic radicals and counterions in ionic liquids are dominantly contributed from the electrostatic term, while the orbital interaction plays a major role in other interactions. The results reported herein are important to understand radical processes in ionic liquids and will be very useful in the design of task-specific ionic liquids to make the processes more efficient.

6.
Appl Opt ; 55(15): 4123-31, 2016 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-27411141

RESUMO

Advances in the field of three-dimensional (3D) scanning have made the acquisition of 3D range data easier and easier. However, with the large size of 3D range data comes the challenge of storing and transmitting it. To address this challenge, this paper presents a framework to further compress 3D range data using image interpolation. We first use a virtual fringe-projection system to store 3D range data as images, and then apply the interpolation algorithm to the images to reduce their resolution to further reduce the data size. When the 3D range data are needed, the low-resolution image is scaled up to its original resolution by applying the interpolation algorithm, and then the scaled-up image is decoded and the 3D range data are recovered according to the decoded result. Experimental results show that the proposed method could further reduce the data size while maintaining a low rate of error.

7.
Crit Rev Oncol Hematol ; 197: 104330, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38556071

RESUMO

Sialic acid (SA), as the ultimate epitope of polysaccharides, can act as a cap at the end of polysaccharide chains to prevent their overextension. Sialylation is the enzymatic process of transferring SA residues onto polysaccharides and is catalyzed by a group of enzymes known as sialyltransferases (SiaTs). It is noteworthy that the sialylation level of glycoproteins is significantly altered when digestive cancer occurs. And this alteration exhibits a close correlation with the progression of these cancers. In this review, from the perspective of altered SiaTs expression levels and changed glycoprotein sialylation patterns, we summarize the pathogenesis of gastric cancer (GC), colorectal cancer (CRC), pancreatic ductal adenocarcinoma (PDAC), and hepatocellular carcinoma (HCC). Furthermore, we propose potential early diagnostic biomarkers and prognostic indicators for different digestive cancers. Finally, we summarize the therapeutic value of sialylation in digestive system cancers.


Assuntos
Biomarcadores Tumorais , Glicoproteínas , Sialiltransferases , Humanos , Sialiltransferases/metabolismo , Biomarcadores Tumorais/metabolismo , Glicoproteínas/metabolismo , Ácido N-Acetilneuramínico/metabolismo , Neoplasias do Sistema Digestório/metabolismo , Neoplasias do Sistema Digestório/diagnóstico , Terapia de Alvo Molecular/métodos , Animais
8.
Nat Commun ; 15(1): 391, 2024 Jan 09.
Artigo em Inglês | MEDLINE | ID: mdl-38195579

RESUMO

Clean water and sanitation are major global challenges highlighted by the UN Sustainable Development Goals. Water treatment using energy-efficient membrane technologies is one of the most promising solutions. Despite decades of research, the membrane permeability-selectivity trade-off remains the major challenge for synthetic membranes. To overcome this challenge, here we develop a two-dimensional cobalt-functionalized vermiculite membrane (Co@VMT), which innovatively combines the properties of membrane filtration and nanoconfinement catalysis. The Co@VMT membrane demonstrates a high water permeance of 122.4 L·m-2·h-1·bar-1, which is two orders of magnitude higher than that of the VMT membrane (1.1 L·m-2·h-1·bar-1). Moreover, the Co@VMT membrane is applied as a nanofluidic advanced oxidation process platform to activate peroxymonosulfate (PMS) for degradation of several organic pollutants (dyes, pharmaceuticals, and phenols) and shows excellent degradation performance (~100%) and stability (for over 107 h) even in real-world water matrices. Importantly, safe and non-toxic effluent water quality is ensured by the Co@VMT membrane/PMS system without brine, which is totally different from the molecular sieving-based VMT membrane with the concentrated pollutants remaining in the brine. This work can serve as a generic design blueprint for the development of diverse nanofluidic catalytic membranes to overcome the persistent membrane permeability-selectivity issue in water purification.

9.
Materials (Basel) ; 17(11)2024 Jun 02.
Artigo em Inglês | MEDLINE | ID: mdl-38893953

RESUMO

Ionic liquids (ILs) based on hybrid anions have recently garnered attention as beguiling alternative electrolytes for energy storage devices. This attention stems from the potential of these asymmetric anions to reduce the melting point of ILs and impede the crystallization of ILs. Furthermore, they uphold the advantages associated with their more conventional symmetric counterparts. In this study, we employed dispersion-corrected density functional theory (DFT-D) calculations to scrutinize the interplay between two hybrid anions found in ionic liquids [FTFSA]- and [MCTFSA]- and the [C4mpyr]+ cation, as well as in lithium polysulfides in lithium-sulfur batteries. For comparison, we also examined the corresponding ILs containing symmetric anions, [TFSA]- and [FSA]-. We found that the hybrid anion [MCTFSA]- and its ionic liquid exhibited exceptional stability and interaction strength. Additionally, our investigation unveiled a remarkably consistent interaction between ionic liquids (ILs) and anions with lithium polysulfides (and S8) during the transition from octathiocane (S8) to the liquid long-chain Li2Sn (4 ≤ n ≤ 8). This contrasts with the gradual alignment observed between cations and lithium polysulfides during the intermediate state from Li2S4 to the solid short-chain Li2S2 and Li2S1. We thoroughly analyzed the interaction mechanism of ionic liquids composed of different symmetry anions and their interactions with lithium polysulfides.

10.
Comput Intell Neurosci ; 2022: 9040349, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36188699

RESUMO

Under the modern environment, the reconstruction of enterprise's core competitiveness depends not only on capital and technical strength, but also on the overall strength of its human resources. At the same time, effective allocation and rational use of talents are needed to create good performance for enterprises. Enterprise human resource management is the key part of the whole enterprise management. At the same time, it is also a necessary preparation for the continuous development and innovation of enterprises. In the whole process of human resource management, the core work is person-post matching. Only by promoting the reasonable implementation of person-post matching can other management work be carried out smoothly. This paper expounds two major elements in human resource management, namely, the concept and measurement of person-post matching and the principle of person-post matching. And the factors in the matching of people and posts are analyzed. This paper probes into the implementation of person-post matching in enterprise human resource management. Based on this, this paper puts forward a depth model of accurate matching between people and posts based on ability perception. On the basis of studying the optimization of human resource scheduling, this paper takes into account three factors: resource constraints, heterogeneity of employee efficiency and time sequence relationship, and uses integer linear programming theory to model the system with the shortest construction period as the goal. The research shows that the accuracy of this algorithm can reach about 94%, which is about 8% higher than the traditional algorithm. It has certain superior performance. This will provide some reference for related researchers.


Assuntos
Algoritmos , Percepção , Humanos
11.
Chem Commun (Camb) ; 58(53): 7376-7379, 2022 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-35699117

RESUMO

Herein, tetraethylammonium 1,2,3-triazolide ([Et4N][Tz]), 1,2,3-triazole (Tz), and ethylene glycol (EG) are used to form DESs for CO2 capture. Surprisingly, [Et4N][Tz]-EG DESs can react with CO2, but [Et4N][Tz]-Tz cannot react with CO2, although both of the two systems contain the same anion [Tz]-. Unexpectedly, with the addition of EG to [Et4N][Tz]-Tz, the formed ternary DESs [Et4N][Tz]-Tz-EG can react with CO2, although neither EG nor [Et4N][Tz]-Tz can react with CO2 before the combination of them. NMR, FTIR and theoretical calculation results disclose that the surprise CO2 absorption behavior mainly depends on the strength of hydrogen bonds (H-bonds) between the anion [Tz]- and H-bond donors (EG or Tz). The strength of the H-bond between [Tz]- and Tz is much stronger than that between [Tz]- and EG. The strong H-bond between [Tz]- and Tz in [Et4N][Tz]-Tz greatly reduces the basicity of [Tz]-, rendering the anion [Tz]- unreactive to CO2. In [Et4N][Tz]-Tz-EG ternary DESs, EG competes with Tz to form a H-bond with [Tz]-, which weakens the strength of the H-bond between [Tz]- and Tz. Moreover, H-bonds also impact the desorption behavior. [Et4N][Tz] : EG (1 : 2) is regenerated at 60 °C, whereas the chemisorbed CO2 by [Et4N][Tz] : Tz : EG (1 : 2 : 2) can be released even down to 30 °C.

12.
ACS Omega ; 7(23): 19513-19520, 2022 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-35721893

RESUMO

In this work, we proposed a facile dissolution-crystallization strategy based on density functional theory calculations to achieve rapid as well as uniform distribution of sulfur on porous carbon. Sulfur-containing solution can completely penetrate porous material and in preference remove into the pores under the influence of capillary force, and sulfur tends to crystallize on the defective even non-defective carbon matrix rather than agglomerate. The S/PC composites prepared by this method can still achieve uniform distribution of sulfur when the sulfur content is as high as 85%. All operations can be completed within a few minutes without any heating. Compared with common melt-diffusion and vapor-phase infusion, this approach has lower energy consumption and is simple, safe, continuous, and rapid.

13.
Sci Total Environ ; 814: 152698, 2022 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-34974016

RESUMO

Heterogeneous advanced oxidation processes (AOPs) are commonly employed for the degradation of recalcitrant contaminants, however, practical application of heterogeneous AOPs has been limited by their low activation efficiency and inefficient utilization of radicals. Herein, this study demonstrates for the first time that 2D honeycomb-like holey membranes assembled by Co3O4 nanosheets, serve as an excellent activator for peroxymonosulfate (PMS) and aid in rapid pollutant removal. The Co3O4 membrane achieved 100% target pollutant ranitidine removal and a membrane retention time of only ~385 ms with the degradation rate 3-5 orders of magnitude faster than that achieved by conventional heterogeneous catalysis. Ranitidine degradation was maintained at >90% for 13 h of continuous-flow operation at a high flux of 176 L m-2 h-1 bar-1. Furthermore, the Co3O4 membrane could also effectively degrade several recalcitrant pollutants, including pharmaceutical personal care products, phenols, and dyes. SO4•- and •OH were identified as the primary reactive oxygen species in the Co3O4 membrane/PMS system, with Co providing the active site for PMS activation. This strategy of membrane-based AOP treatment offers helpful guidance for the design of other efficient heterogeneous catalytic systems and presents a novel approach to overcoming the limitations of conventional heterogeneous catalysis.


Assuntos
Cobalto , Peróxidos , Óxidos
14.
Phytomedicine ; 102: 154171, 2022 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-35636165

RESUMO

BACKGROUND: Pulmonary hypertension (PH) is a progressive disorder lacking a validated and effective therapy which characterized by elevated pulmonary arterial pressure, vascular remodeling and eventual death. FDA approved sildenafil is being used as a first-line drug for PH, however, neither survival rates nor quality of life have been improved because of side effects and patient noncompliance. Thus, the exploration of novel therapeutic drugs is urgently needed. Astragaloside IV (ASIV) exhibits a protective effect on HPH, but its mechanisms of action is unclear. HYPOTHESIS: CD4+T cell subsets, Tfh and Tfr cells, may contribute to the development of chronic hypoxia-induced PH (HPH). We hypothesized that ASIV could effectively ameliorates pulmonary vascular remodeling of HPH by restraining the Tfh cell response and expanding Tfr cell response. METHODS AND RESULTS: HPH mice model was established by exposure to chronic hypoxia for 21 days. Mice were randomly assigned to six groups: NaCl group, model group, SN group (100 mg/kg of sildenafil), low-dose group (20 mg/kg of ASIV), medium-dose group (40 mg/kg of ASIV) and high-dose group (80 mg/kg of ASIV). Primary culture and identification of distal pulmonary artery smooth muscle cells (PASMCs) in mice were established. Here, we demonstrated that ASIV treatment could significantly ameliorate the increase of mean PAP, RV/ (LV+S) ratio and PAMT in HPH mice. ASIV inhibited Tfh cell differentiation and IL-21 production, but promoted Tfr cell differentiation and TGF-ß, IL-10 production. Chronic hypoxia promoted germinal center B cell responses, which inhibited by ASIV. ASIV regulated Tfh and Tfr cell differentiation by inhibiting the phosphorylation of mTOR signaling pathway, and the effect of ASIV-H was better than that observed in the SN group. ASIV inhibited the proliferation, migration and adhesion of PASMCs in vitro. Moreover, ASIV significantly downregulated the protein level of RhoA and upregulated the protein level of p27 in PASMCs under hypoxic condition. CONCLUSION: Collectively, ASIV may regulate Tfh and Tfr cell responses to subsequently repress pulmonary vascular remodeling and hypoxic pulmonary hypertension.


Assuntos
Hipertensão Pulmonar , Animais , Hipertensão Pulmonar/tratamento farmacológico , Hipertensão Pulmonar/etiologia , Hipóxia/complicações , Hipóxia/tratamento farmacológico , Camundongos , Artéria Pulmonar , Qualidade de Vida , Saponinas , Citrato de Sildenafila/metabolismo , Citrato de Sildenafila/farmacologia , Citrato de Sildenafila/uso terapêutico , Células T Auxiliares Foliculares , Triterpenos , Remodelação Vascular
15.
Nat Commun ; 13(1): 4010, 2022 07 11.
Artigo em Inglês | MEDLINE | ID: mdl-35817796

RESUMO

The freshwater scarcity and inadequate access to clean water globally have rallied tremendous efforts in developing robust technologies for water purification and decontamination, and heterogeneous catalysis is a highly-promising solution. Sub-nanometer-confined reaction is the ultimate frontier of catalytic chemistry, yet it is challenging to form the angstrom channels with distributed atomic catalytic centers within, and to match the internal mass transfer and the reactive species' lifetimes. Here, we resolve these issues by applying the concept of the angstrom-confined catalytic water contaminant degradation to achieve unprecedented reaction rates within 4.6 Å channels of two-dimensional laminate membrane assembled from monolayer cobalt-doped titanium oxide nanosheets. The demonstrated degradation rate constant of the target pollutant ranitidine (1.06 ms-1) is 5-7 orders of magnitude faster compared with the state-of-the-art, achieving the 100% degradation over 100 h continuous operation. This approach is also ~100% effective against diverse water contaminates with a retention time of <30 ms, and the strategy developed can be also extended to other two-dimensional material-assembled membranes. This work paves the way towards the generic angstrom-confined catalysis and unravels the importance of utilizing angstrom-confinement strategy in the design of efficient catalysts for water purification.


Assuntos
Poluentes Químicos da Água , Purificação da Água , Catálise , Água , Poluentes Químicos da Água/análise , Purificação da Água/métodos
16.
ACS Appl Mater Interfaces ; 12(9): 10893-10901, 2020 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-32045196

RESUMO

Graphene oxide (GO)-based membranes have displayed superior performances in the chiral resolution compared with conventional polymer-based and inorganic membranes. However, the effect of the host-guest interaction between chiral selectors and probes on the enantioseparation properties of GO-based membranes remains to be established. In this work, l-phenylalanine (l-Phe, as the chiral selector)-modified GO-based (l-Phe-GO) membranes were fabricated, and their enantioseparation performances toward various enantiomers, that is, d- and l-phenylalanine (d- and l-Phe), d- and l-methionine (d- and l-Met), N-acyl-d-phenylalanine (N-acyl-d-Phe) and N-acyl-l-phenylalanine (N-acyl-l-Phe), and N-acyl-d-methionine (N-acyl-d-Met) and N-acyl-l-methionine (N-acyl-l-Met), were detected. Results show that (i) l-Phe is preferential to transport d-enantiomers relative to l-enantiomers; (ii) as far as d-enantiomers are concerned, the d-Phe-like enantiomers move faster than d-Met-like ones through the l-Phe-GO membrane owing to their different host-guest interactions. The strength of interactions between chiral selectors and probes was further confirmed from both experimental and theoretical standpoints. In the former case, the enantioselective adsorption of l-Phe-GO nanosheets toward the aforementioned enantiomers demonstrates that l-Phe delivers a higher adsorption capacity to d-enantiomers relative to l-enantiomers, and meanwhile, d-Phe-like enantiomers are better than d-Met-like enantiomers in the adsorption capacity. In the latter case, the chiral separation mechanism is clarified using the periodical density functional theory (DFT) calculation, indicating that l-Phe interacts with d-enantiomers more strongly than l-enantiomers. Especially, our calculations unveil that the difference in the interaction strength is principally dominated by the nonstereoselective interactions between chiral probes and the GO surface. Therefore, our findings suggest that the nonstereoselective weak interaction can be employed to improve the enantioselectivity of GO-based membranes.

17.
Front Chem ; 8: 731, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32974284

RESUMO

Water clusters are ubiquitously formed in aqueous solutions by hydrogen bonding, which is quite sensitive to various environment factors such as temperature, pressure, electrolytes, and pH. Investigation of how the environment has impact on water structure is important for further understanding of the nature of water and the interactions between water and solutes. In this work, pH-dependent water structure changes were studied by monitoring the changes for the size distribution of protonated water clusters by in-situ liquid ToF-SIMS. In combination with a light illumination system, in-situ liquid ToF-SIMS was used to real-time measure the changes of a light-activated organic photoacid under different light illumination conditions. Thus, the proton transfer and pH-mediated water cluster changes were analyzed in real-time. It was found that higher concentration of free protons could lead to a strengthened local hydrogen bonding network as well as relatively larger protonated water clusters in both organic acid and inorganic acid. Besides, the accumulation of protons at the liquid-vacuum interface under light illumination was observed owing to the affinity of organic molecules to the low-pressure gas phase. The application of in-situ liquid ToF-SIMS analysis in combination with in-situ light illumination system opened up an avenue to real-time investigate light-activated reactions. Besides, the results regarding water structure changes in acidic solutions showed important insights in related atmospheric and physiochemical processes.

19.
ACS Appl Bio Mater ; 2(2): 943-951, 2019 Feb 18.
Artigo em Inglês | MEDLINE | ID: mdl-35016298

RESUMO

Fluorescence imaging is critical for physiological activities and cell biology but limited by the poor solubility, cell compatibility, and permeability. Herein, we develop a novel engineering methodology to prepare biocompatible and penetrable aggregation-induced emission (AIE) nanoparticles with the assistance of flash nanoprecipitation (FNP) technology. On the basis of the donor-π-acceptor (D-π-A) system, the AIE building block of tricyano-methylene-pyridine (TCM) is fine-tuned to long emission wavelength by modulating the π-conjugation bridge and electron-donating group, thereby achieving high solid fluorescent quantum yield, near-infrared (NIR) characteristic, large Stokes shift, and excellent photostability. On the basis of the FNP technology, the amphiphilic saponin solution and TCMN-5 in organic solvent are quickly mixed in the multi-inlet vortex mixer (MIVM), followed by saponin-encapsulation of the hydrophobic AIE nucleation with inhibiting further growth of nanoparticles. The biocompatible amphiphilic saponin such as α-hederin can encapsulate and micellize the AIE TCM fluorophore for efficient cell imaging. The kinetic FNP technology can not only modulate the uniform diameter size, but also distinctly increase the micelle stability when compared to the conventional thermodynamic self-aggregation method, which provides an alternative opportunity for scale-up preparation of drugs and probes in delivery vehicles.

20.
J Phys Chem Lett ; 10(17): 4935-4941, 2019 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-31403310

RESUMO

The hydrogen bond (HB), one of the essential properties of water, tends to link water molecules to form dynamic water clusters. Extrinsic ions could change the size distribution of water clusters by influencing HBs. But the mechanism, especially the influence range of ions on HBs, is still in dispute due to limitation of analytical methods. Herein, we use in situ liquid ToF-SIMS analysis combined with density functional theory calculation to study the influence of different halide anions on HBs at a submicropore confined liquid-vacuum interface. Our experimental results demonstrated that anions show synchronous local and long-range effects on HBs. Specifically, the larger the anion is, the greater degree the long-range HB network and the local hydration number of anions are influenced. More importantly, we found that the long-range effect on the HB network is influenced by nuclear quantum effects, whereas the local effect on water molecules in the first hydration shell is not.

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