Nanofluids have increasingly drawn interest in recent years with their various applications in a number of fields. The method for the preparation of stable nanofluids is a key concern for extending ...the application of nanofluids. This study focuses on the effect of pH, dosage of surfactant (TX-100), and nanofluid concentration on the stability of a silica nanofluid. Particle size and zeta potential are two important factors to consider in evaluating the stability of the silica nanofluid. Results indicate that the stability of the silica nanofluid highly depends on pH, dosage of surfactant (TX-100), and nanofluid concentration. On the basis of these experiments, the best conditions for the preparation of a silica nanofluid are 0.1 wt. % for the concentration of silica nanoparticles and TX-100 and 10 for pH. A transparent and stable silica nanofluid can thus be obtained.
•A novel strategy to create fluorescence nanoprobe is developed.•Thiol-ene click reaction is used to synthesize materials containing QDs.•The separated BSQD nanoprobes could be well-dispersed into ...water once again.•Fluorescence probe shows interfacial activity, photostability and biocompatibility.•Successfully fluorescence imaging application of BSQDs nanoprobes in porous media.
Quantum dots (QDs) as fluorescence probes have attracted increasing attention for their fluorescence imaging applications. In this work, we developed a novel strategy to create bifunctional silica-protected QD (BSQD) nanoparticles as nanoprobes for fluorescence imaging. The thiol-ene click reaction of monounsaturated fatty acid salts with mercapto silane as an efficient method for the synthesis of the bifurcated surface modifier was presented. BSQD nanoprobes were prepared by a facile one-pot method. The whole reaction process was carried out in an aqueous solution under relatively low temperature, which makes the synthesis environment eco-friendly and the products cost-effective. The synthesized BSQD nanoprobes have a structure consisting of hydrophilic and hydrophobic arms that afforded an amphiphilic feature to the silica-protected QD (SQD) nanoparticles. The separated solid BSQD nanoprobes could be well dispersed into aqueous solution once again, and the quantum yield of the BSQD nanoprobes was higher than that of the SQD naoprobes. BSQD nanoprobes exhibited high interfacial activity, strong photostability and good biocompatibility. BSQD nanoprobes were successfully applied for fluorescence imaging. The strategy for the construction of the functionalized SQD nanoparticles provides a promising approach for modifying the surface of materials containing QDs.
(1) Background: Deubiquitinase (DUB) regulates various important cellular processes via reversing the protein ubiquitination. The N-terminal fragment of a giant tegument protein, UL36, encoded by the ...Marek's disease (MD) virus (MDV), encompasses a putative DUB (UL36-DUB) and shares no homology with any known DUBs. The N-terminus 75 kDa fragment of UL36 exists in MD T lymphoma cells at a high level and participates in MDV pathogenicity. (2) Methods: To characterize deubiquitinating activity and substrate specificity of UL36-DUB, the UL36 N-terminal fragments, UL36(323), UL36(480), and mutants were prepared using the Bac-to-Bac system. The deubiquitinating activity and substrate specificity of these recombinant UL36-DUBs were analyzed using various ubiquitin (Ub) or ubiquitin-like (UbL) substrates and activity-based deubiquitinating enzyme probes. (3) Results: The results indicated that wild type UL36-DUBs show a different hydrolysis ability against varied types of ubiquitin chains. These wild type UL36-DUBs presented the highest activity to K11, K48, and K63 linkage Ub chains, weak activity to K6, K29, and K33 Ub chains, and no activity to K27 linkage Ub chain. UL36 has higher cleavage efficiency for K48 and K63 poly-ubiquitin than linear ubiquitin chain (M1-Ub4), but no activity on various ubiquitin-like modifiers. The mutation of C98 and H234 residues eliminated the deubiquitinating activity of UL36-DUB. D232A mutation impacted, but did not eliminated UL36(480) activity. The Ub-Br probe can bind to wild type UL36-DUB and mutants UL36(480)
and UL36(480)
, but not C98 mutants. These in vitro results suggested that the C98 and H234 are essential catalytic residues of UL36-DUB. UL36-DUB exhibited a strict substrate specificity. Inhibition assay revealed that UL36-DUB exhibits resistance to the Roche protease inhibitor cocktail and serine protease inhibitor, but not to the Solarbio protease inhibitor cocktail. (4) Conclusions: UL36-DUB exhibited a strict substrate preference, and the protocol developed in the current study for obtaining active UL36-DUB protein should promote the high-throughput screening of UL36 inhibitors and the study on the function of MDV-encoded UL36.
Ubiquitination and deubiquitination of cellular proteins are reciprocal reactions catalyzed by ubiquitination-related enzymes and deubiquitinase (DUB) which regulate almost all cellular processes. ...Marek's disease virus (MDV) encodes a viral DUB that plays an important role in the MDV pathogenicity. Chicken CD4
T-cell lymphoma induced by MDV is a key contributor to multiple visceral tumors and immunosuppression of chickens with Marek's disease (MD). However, alterations in the ubiquitylome of MDV-induced T lymphoma cells are still unclear. In this study, a specific antibody against K-ε-GG was used to isolate ubiquitinated peptides from CD4
T cells and MD T lymphoma cells. Mass spectrometry was used to compare and analyze alterations in the ubiquitylome. Our results showed that the ubiquitination of 717 and 778 proteins was significantly up- and downregulated, respectively, in T lymphoma cells. MDV up- and downregulated ubiquitination of a similar percentage of proteins. The ubiquitination of transferases, especially serine/threonine kinases, was the main regulatory target of MDV. Compared with CD4
T cells of the control group, MDV mainly altered the ubiquitylome associated with the signal transduction, immune system, cancer, and infectious disease pathways in T lymphoma cells. In these pathways, the ubiquitination of CDK1, IL-18, PRKCB, ETV6, and EST1 proteins was significantly up- or downregulated as shown by immunoblotting. The current study revealed that the MDV infection could exert a significant influence on the ubiquitylome of CD4
T cells.
Interleukin-2 (IL-2) is a pleiotropic cytokine regulating the immune and nervous systems. Mammalian and bird IL-2s have different protein sequences, but perform similar functions. In the current ...study, two bands were detected by immunoblotting using an antibody against freshly purified chicken IL-2 (chIL-2). The molecular weight of the larger band was approximately twice as much of the chIL-2 monomer, although a chIL-2 complex or homodimer has never been reported. To explain this intriguing result, several dissociation reagents were used to examine the intermolecular forces between components of the proposed chIL-2 complex. It was found that intermolecular disulphide bond promotes homodimerization of chIL-2. Subsequently, mutation of Cys residues of chIL-2 revealed that mutation of all four Cys residues disrupted homodimerization, but a single, dual, or triple Cys mutation failed to disrupt homodimerization, suggesting that all four Cys residues on chIL-2 contribute to this dimerization. Functional analysis showed that both monomeric and dimeric chIL-2 consisting of either wild type or mutant chIL-2 were able to stimulate the expansion of CD4
T cell in vivo or in vitro, and effectively bind to chIL-2 receptor. Overall, this study revealed that the recombinant chIL-2 purified from either
(
) or
(Sf9) cells could homodimerize in vitro, with all four Cys residues on each chIL-2 protein contributing to this homodimerization, and dimerization and Cys mutation not impacting chIL-2 induced stimulation of chicken CD4
T cells.
PURPOSEThis study aims to assess the diagnostic value of ultrasound habitat sub-region radiomics feature parameters using a fully connected neural networks (FCNN) combination method L2,1-norm in ...relation to breast cancer Ki-67 status.METHODSUltrasound images from 528 cases of female breast cancer at the Affiliated Hospital of Xiangnan University and 232 cases of female breast cancer at the Affiliated Rehabilitation Hospital of Xiangnan University were selected for this study. We utilized deep learning methods to automatically outline the gross tumor volume and perform habitat clustering. Subsequently, habitat sub-regions were extracted to identify radiomics features and underwent feature engineering using the L1,2-norm. A prediction model for the Ki-67 status of breast cancer patients was then developed using a FCNN. The model's performance was evaluated using accuracy, area under the curve (AUC), specificity (Spe), positive predictive value (PPV), negative predictive value (NPV), Recall, and F1. In addition, calibration curves and clinical decision curves were plotted for the test set to visually assess the predictive accuracy and clinical benefit of the models.RESULTBased on the feature engineering using the L1,2-norm, a total of 9 core features were identified. The predictive model, constructed by the FCNN model based on these 9 features, achieved the following scores: ACC 0.856, AUC 0.915, Spe 0.843, PPV 0.920, NPV 0.747, Recall 0.974, and F1 0.890. Furthermore, calibration curves and clinical decision curves of the validation set demonstrated a high level of confidence in the model's performance and its clinical benefit.CONCLUSIONHabitat clustering of ultrasound images of breast cancer is effectively supported by the combined implementation of the L1,2-norm and FCNN algorithms, allowing for the accurate classification of the Ki-67 status in breast cancer patients.
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•A new homeostatic system based on stimuli-responsive materials as building blocks.•Smart capsules sense surrounding changes and start internal communication by releasing energy-rich ...cargo.•Active microgels complete closed-loop communication through enzymatic reaction networks.•The system exhibits programmable interactive communications and self-regulation behaviour.
Biological systems possess unique non-equilibrium functions, maintaining tight manipulation of their surroundings through inter-communication of multiple components and self-regulatory capability organized over different length scales. However, most artificial materials are incapable of communicating and self-regulating behavior due to their limited number of component and direct responsive modes. Herein, a new integrated self-regulation system is developed utilizing stimuli-responsive polyelectrolyte capsules as building blocks. The combination of stimuli-responsive capsules and enzyme immobilized microgels is designed to mimic life systems and its programmable interactive communications and self-regulation behavior is demonstrated through communication-feedback mechanism. Polyelectrolyte capsules can sense changes of their surrounding, then start the internal communication by releasing energy-rich cargo mimicking the behavior of the cells. The microgel particles subsequently complete closed-loop communication through providing negative feedback on capsules by enzymatic reaction and actuating pH-regulation of the whole system. Different communication modes and pH-regulation behaviors could be achieved by adjusting spatial and kinetic conditions. Proposed intelligent system is highly customizable due to the wide selection of encapsulated cargos, stimuli-responsive blocks and reaction networks, and would have broad influences in areas ranging from medical implants that assist in stabilizing body functions to microreactor system that regulate catalytic reactions.
In this work, we employed NMR technique to monitor the migration rule of nanofluid in sandstone cores during the spontaneous imbibition process. And EOR mechanism of the nanofluid was discussed.
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•A novel nanofluid based on functional silica nanoparticles was prepared.•Imbibition and NMR measurement were combined to monitor oil distribution.•70.82–71.98 wt% of oil was distributed in mesopores (50 nm < pore size ≤ 3000 nm).•The NMR spectra and imaging show that the nanoparticles seeped into the core.
Spontaneous imbibition of nanofluid has attracted much interest in enhanced oil recovery (EOR) in ultralow permeable reservoirs. However, the oil distribution in ultralow permeable cores during the spontaneous imbibition using nanofluids has not been discussed in detail. In this study, imbibition experiment and nuclear magnetic resonance (NMR) measurement were used to monitor the migration rule of nanofluid and oil distribution in the imbibition. The results show that 70.82–71.98 wt% of the oil was distributed in mesopores (50 nm < pore size ≤ 3000 nm). The final oil recoveries of cores immersed in different concentrations of nanofluids (0.1 wt%, 0.05 wt%, 0.01 wt%, and 0.005 wt%) and brine were 32.5%, 26.9%, 20.5%, 15.1%, and 8.3%, respectively. The NMR spectra and imaging show that the nanoparticles seeped into the core. Significant insight into the oil distribution during the imbibition of nanofluid is provided.
•The oil migration behavior during dynamic imbibition are studied by nuclear magnetic resonance.•The boundary of cores are semi-sealed to simulate practical condition.•Four characteristic points of ...the T2 spectrum are selected, the oil recovery in these pores are identified.•The effects of surfactant injection rate, interfacial tension, soaking time, and permeability on oil recovery are investigated in detail.
Dynamic imbibition is an imbibition phenomenon considering fluid flow around the surface of porous media and plays an important role in the development of tight oil reservoirs. In this paper, the behavior of oil migration in nanometer to micrometer sized pores during dynamic imbibition was studied using nuclear magnetic resonance (NMR). Firstly, the basic properties of surfactant and core samples were characterized. The boundary of cores were semi-sealed to simulate practical conditions. The dynamic imbibition experiments were carried out in the core flooding system using low-field NMR. The T2 spectrum and magnetic resonance imaging (MRI) were scanned, and the T2 relaxation time was converted to pore sizes using the mercury injection curve. The oil recovery factor and capillary number in nanopores and macropores were calculated. Four characteristic points of T2 spectrum were selected, and the recovery of these characteristic pores (0.3, 0.6, 18.3, and 116.7 μm) were found to be 20.0%, 19.8%, 11.9%, 30.1%, respectively. Furthermore, the effects of injection rate, interfacial tension (IFT), soaking time, and permeability on oil recovery from different typical pore sizes were investigated in detail. The recovery factor ratio (r), which was defined as the ratio of oil recovery in nanometer pores to that of macrometer pores, increased with the increase in soaking time, IFT, and permeability, while it decreased with the increase in flow rate.
Interests in using nanofluids for enhanced oil recovery (EOR) applications has been increasing. Herein, a novel surfactant-free water-based nanofluid for EOR was constructed using active silica ...nanoparticles. Active silica nanoparticles were synthesized via condensation of hexanedioic acid with the −OH group of silica. Water-based nanofluid was obtained by transforming carboxyl into carboxylate on the surface of active silica nanoparticles in water. The particle size of the active silica nanoparticles in water ranged from 10 to 20 nm. The interfacial activity of the nanoparticles was endowed through the shape change of the active silica nanoparticle surface groups to minimize their interface energy. The morphology and surface components of the active silica nanoparticles were characterized by transmission electron microscopy and Fourier transform infrared spectroscopy. The interfacial activity of the active silica nanoparticles was proved through interfacial tension and interfacial dilational modulus measurements. Active silica nanoparticles exhibited a stronger ability to reduce interfacial tension and enhance the interfacial film strength than silica nanoparticles. Contact angle measurements showed that this nanofluid exhibited excellent capabilities of oil displacement from a solid surface and wettability alteration. Spontaneous imbibition tests of ultralow permeability cores using different liquid phases (active silica nanofluid, silica nanofluid and brine) were conducted. Oil recovery using active silica nanofluid was higher than that of using silica nanofluid or brine. Active silica nanofluid at a low concentration could display an equal EOR efficiency with highly concentrated silica nanofluid. These results indicated the possible application of the proposed active silica water-based nanofluid in EOR. This preparation method could be used to prepare surfactant-free active nanofluids, and the surfactant-free active nanofluid shows great potential for EOR applications.
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