This study describes the preparation of hydrogen bonding connected micelles, consisting of a poly(styrene-
-(
-hydroxyphenylmaleimide)) poly(S-
-pHPMI) core and a poly(4-vinylpyridine) (P4VP) ...derivative shell in a selective solvent. The aim was to modify hydrogen bonding interaction sites at the core/shell interface by synthesizing P4VP derivatives in three different sequences, namely, P4VP homopolymers, PS-
-P4VP random copolymers, and block copolymers. TEM images showed the successful self-assembly of poly(S-
-pHPMI)/PS-
-P4VP inter-polymer complexes into spherical structures. To dissolve the core structures, 1,4-dibromobutane was used as a cross-linking agent to tighten the PS-
-P4VP shell. The morphologies, particle sizes, hydrogen bonding, cross-linking reaction, and core dissolution were confirmed by TEM, DLS, FTIR, and AFM analyses. Poly(S-
HPMI)/PS
-
-P4VP
hydrogen bonding connected micelles, cross-linked micelles, and hollow spheres were larger and more irregular than poly(S-
HPMI)/P4VP inter-polymer complexes due to the random copolymer architecture and the decrease in intermolecular hydrogen bonds. However, poly(S-
HPMI)/PS
-
-P4VP
resulted in rod- or worm-like structures after core dissolution.
In this study we used classical Suzuki polycondensation to prepare a pyridinyl-phenanzine (TPPQP) conjugated microporous polymer (CMP) that featured a spherical morphology with a large surface area ...(371 m2 g−1) and high thermal stability (Td10 = 625 °C; char yield = 81.7 wt%). The framework of the TPPQP CMP presented many dynamic pyridinic units could capture Ag+ ions from solution and facilitate their self-reduction to Ag nanoparticles, thereby forming Ag@TPPQP CMP nanocatalysts. The Ag@TPPQP CMP nanocatalysts were strong reducing agents for pollutant nitrophenols, converting them into safe amino forms at standard temperature and pressure with a high normalized rate of 19.4 mg−1 s−1. The pyridinic units in the TPPQP CMP structure played an important role in the catalytic reaction, interacting with the phenolic OH groups of p-nitrophenol to accelerate the reduction.
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•The conjugated microporpous polymer through Suzuki coupling polycondensation.•The TPP-QP CMP self-reduced silver ions and granted a Ag@TPPQP nanocatalyst.•The Ag@TPPQP CMP nanocatalyst featured high catalytic performance up to 19.4 mg−1 s−1.
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•A novel approach for the fabrication of luminescent hollow spherical nanoparticles.•the construction of HBCMs utilizing inter-polymer complexes of poly(S-alt-HPMI)/P4VP).•The ...formation of self-assembled spherical structures formed by poly(S-alt-HPMI)/P4VP inter-polymer complexes.•This approach demonstrates significant promise for utilization in nano-carriers, offering enhanced imaging contrast.
Herein, we propose an innovative method for synthesizing luminescent hollow spherical nanoparticles. Our method involves the construction of hydrogen bonding connected micelles (HBCMs) utilizing inter-polymer complexes of poly(styrene-alt-hydroxyphenylmaleimide)/poly(4-vinylpyridine) (poly(S-alt-HPMI)/P4VP), which could undergo self-assembly, resulting in the formation of core/shell nanostructures in the selective solvent. The aim was to incorporate two types of fluorescent compounds, namely tris(4–bromophenyl)amine (TPA–Br3) and 1,1,2,2–tetrakis(4–bromophenyl)ethene (TPE–Br4), as the cross-linkers to enhance the shell structures of HBCMs and using dimethylformamide (DMF) was employed to remove the core structures, aiming to pursue the formation of luminescent hollow spheres. Transmission electron microscopy (TEM) images confirmed the formation of self-assembled spherical structures formed by poly(S-alt-HPMI)/P4VP inter-polymer complexes. The morphological features, hydrogen bonding interactions, particle sizes, cross-linking reactions, core removal, and thermal properties were thoroughly investigated by TEM, atomic force microscope (AFM), dynamic light scattering (DLS) instrument, Fourier transform infrared (FTIR) spectroscopy, 1H nuclear magnetic resonance (NMR) spectroscopy, thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC) analyses. Moreover, the optical properties were also explored by fluorescence microscope and photoluminescence (PL). This evidence indicates that the HBCMs could be directly cross-linked with TPA–Br3 or TPE–Br4 and subsequently transformed into hollow spheres by the addition of DMF. Fluorescent particles featuring hollow spheres could be prepared successfully without traditional dye staining or labeling. This advancement holds promising potential for applications in nano-carriers with improved imaging contrast.
Circulating levels of granulocyte colony-stimulating factor (G-CSF) and granulocyte macrophage colony-stimulating factor (GM-CSF) are associated with the severity of acute myocardial infarction ...(AMI). However, what causes increases in G-CSF and GM-CSF is unclear. In this study, we investigated whether L5-low-density lipoprotein (LDL), a mildly oxidized LDL from AMI, can induce G-CSF and GM-CSF production in human macrophages.
L1-LDL and L5-LDL were isolated through anion-exchange chromatography from AMI plasma. Human macrophages derived from THP-1 and peripheral blood mononuclear cells were treated with L1-LDL, L5-LDL, or copper-oxidized LDL (Cu-oxLDL) and G-CSF and GM-CSF protein levels in the medium were determined. In addition, the effects of L5-LDL on G-CSF and GM-CSF production were tested in lectin-type oxidized LDL receptor-1 (LOX-1), CD36, extracellular signal-regulated kinase (ERK) 1, and ERK2 knockdown THP-1 macrophages.
L5-LDL but not L1-LDL or Cu-oxLDL significantly induced production of G-CSF and GM-CSF in macrophages. In vitro oxidation of L1-LDL and L5-LDL altered their ability to induce G-CSF and GM-CSF, suggesting that the degree of oxidation is critical for the effects. Knockdown and antibody neutralization experiments suggested that the effects were caused by LOX-1. In addition, nuclear factor (NF)-κB and ERK1/2 inhibition resulted in marked reductions of L5-LDL-induced G-CSF and GM-CSF production. Moreover, knockdown of ERK2, but not ERK1, hindered L5-LDL-induced G-CSF and GM-CSF production.
The results indicate that L5-LDL, a naturally occurring mild oxidized LDL, induced G-CSF and GM-CSF production in human macrophages through LOX-1, ERK2, and NF-κB dependent pathways.
•L5-LDL (the most electronegative LDL) is elevated in STEMI.•L5-LDL induces G-CSF and GM-CSF expression in macrophages through LOX-1.•L5-LDL induces G-CSF and GM-CSF expression through NF-κB and ERK2 dependent pathways.•The degree of oxidation is critical for LDL's induction of G-CSF and GM-CSF production.
Covalent organic frameworks (COFs) have attracted significant interest because of their heteroatom-containing architectures, high porous networks, large surface areas, and capacity to include ...redox-active units, which can provide good electrochemical efficiency in energy applications. In this research, we synthesized two novel hydroxy-functionalized COFs—TAPT-2,3-NA(OH)2, TAPT-2,6-NA(OH)2 COFs—through Schiff-base 3 + 2 polycondensations of 1,3,5-tris-(4-aminophenyl)triazine (TAPT-3NH2) with 2,3-dihydroxynaphthalene-1,4-dicarbaldehyde (2,3-NADC) and 2,6-dihydroxynaphthalene-1,5-dicarbaldehyde (2,6-NADC), respectively. The resultant hydroxy-functionalized COFs featured high BET-specific surface areas up to 1089 m2 g–1, excellent crystallinity, and superior thermal stability up to 60.44% char yield. When used as supercapacitor electrodes, the hydroxy-functionalized COFs exhibited electrochemical redox activity due to the presence of redox-active 2,3-dihydroxynaphthalene and 2,6-dihydroxynaphthalene in their COF skeletons. The hydroxy-functionalized COFs showed specific capacitance of 271 F g−1 at a current density of 0.5 A g−1 with excellent stability after 2000 cycles of 86.5% capacitance retention. Well-known pore features and high surface areas of such COFs, together with their superior supercapacitor performance, make them suitable electrode materials for use in practical applications.
The effect of mechanical force on the free-energy surface that governs a chemical reaction is largely unknown. The combination of protein engineering with single-molecule force-clamp spectroscopy ...allows us to study the influence of mechanical force on the rate at which a protein disulfide bond is reduced by nucleophiles in a bimolecular substitution reaction (S(N)2). We found that cleavage of a protein disulfide bond by hydroxide anions exhibits an abrupt reactivity 'switch' at ∼500 pN, after which the accelerating effect of force on the rate of an S(N)2 chemical reaction greatly diminishes. We propose that an abrupt force-induced conformational change of the protein disulfide bond shifts its ground state, drastically changing its reactivity in S(N)2 chemical reactions. Our experiments directly demonstrate the action of a force-activated switch in the chemical reactivity of a single molecule.
The pedestrian wind environment in a street canyon is affected by a multitude of factors, including the height and geometric shape of the surrounding buildings, the street width, the wind direction, ...and speed. Wind-tunnel tests were performed to determine the effects of constructing high buildings in an urban renewal project in New Taipei City, Taiwan on the pedestrian wind environments in the surrounding street canyons. The results show that replacing the original low-rise buildings with high-rise buildings could decrease the wind speed and natural ventilation potential in certain surrounding street canyons. The flow fields generated by approaching winds in various street canyons are highly complex in this practical case study. Thus, the pedestrian wind patterns in the street canyons cannot be interpreted in terms of channeling and shielding effects alone, as is typically reported in the literature.
is one of the leading bacterial causes of diarrhea worldwide, affecting more than 165 million people annually. Among the serotypes of
is physiologically unique and endemic in human immunodeficiency ...virus-infected men who have sex with men. The NOD-, LRR-, and pyrin domain-containing protein 3 (NLRP3) inflammasome, a protein complex composed of NLRP3, apoptosis-associated speck-like protein, and caspase-1, recognizes, and responds to pathogen infection and diverse sterile host-derived or environmental danger signals to induce IL-1β and IL-18 production. Although the
-mediated activation of the NLRP3 inflammasome has been reported, the effect of
on NLRP3 inflammasome activation remains unclear. We found that
induced IL-1β production through NLRP3-dependent pathways in lipopolysaccharide-primed macrophages. A mechanistic study revealed that
induced IL-1β production through P
X
receptor-mediated potassium efflux, reactive oxygen species generation, lysosomal acidification, and mitochondrial damage. In addition, the phagocytosis of viable
was important for IL-1β production. Furthermore, we demonstrated that NLRP3 negatively regulated phagocytosis and the bactericidal activity of macrophages against
. These findings provide mechanistic insight into the activation of the NLRP3 inflammasome by
in macrophages.
In this study, for the application of visible-light wearable eye trackers, a pupil tracking methodology based on deep-learning technology is developed. By applying deep-learning object detection ...technology based on the You Only Look Once (YOLO) model, the proposed pupil tracking method can effectively estimate and predict the center of the pupil in the visible-light mode. By using the developed YOLOv3-tiny-based model to test the pupil tracking performance, the detection accuracy is as high as 80%, and the recall rate is close to 83%. In addition, the average visible-light pupil tracking errors of the proposed YOLO-based deep-learning design are smaller than 2 pixels for the training mode and 5 pixels for the cross-person test, which are much smaller than those of the previous ellipse fitting design without using deep-learning technology under the same visible-light conditions. After the combination of calibration process, the average gaze tracking errors by the proposed YOLOv3-tiny-based pupil tracking models are smaller than 2.9 and 3.5 degrees at the training and testing modes, respectively, and the proposed visible-light wearable gaze tracking system performs up to 20 frames per second (FPS) on the GPU-based software embedded platform.
This study aims to evaluate the effects of the integrated curriculum on hospitality university students' service attitudes. We adapted a four-stage process to implement an integrated course in ...service-learning and applied the text mining technique to analyze meaningful themes. The findings suggest that university students' reflections indicate a developing understanding of attitudes in the context of hospitality and the acquisition of supporting attributes such as friendliness, empathy, enthusiasm, and problem solving. The attributes are comprised of 71 main themes of service attitude derived from the course. Specific theoretical and practical implications are provided on integrating service-learning into hospitality courses.
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