The synthesis of water-soluble near-infrared (NIR)-emissive fluorescent molecules with aggregation-induced emission (AIE) characteristics and theranostic functions is highly desirable but remains ...challenging. In this work, we designed and readily prepared for the first time such a molecule with AIE features, good water-solubility and intense emission in the NIR region. This AIE luminogen (AIEgen) is able to specifically "light up" the cell membrane without the involvement of a washing procedure. Interestingly, the staining process can be performed by simply shaking the culture with cells at room temperature for only a few seconds after the addition of the AIEgen, indicating an ultrafast and easy-to-operate staining protocol. This is the first fluorescent "light-up" probe for cell-imaging that allows the combination of a short staining period (at the second-level) with a wash-free process. Additionally, the presented AIEgen has also been developed to serve as an excellent phototherapeutic agent for high efficiency generation of reactive oxygen species (ROS) upon visible light irradiation, which allows its effective application in the photodynamic ablation of cancer cells, demonstrating its dual role as an imaging and phototherapeutic agent.
Alzheimer's disease (AD) is the most common cause of dementia worldwide. AD brains display deposits of insoluble amyloid plaques consisting mainly of aggregated amyloid-β (Aβ) peptides, and Aβ ...oligomers are likely a toxic species in AD pathology. AD patients display altered metal homeostasis, and AD plaques show elevated concentrations of metals such as Cu, Fe, and Zn. Yet, the metal chemistry in AD pathology remains unclear. Ni(II) ions are known to interact with Aβ peptides, but the nature and effects of such interactions are unknown. Here, we use numerous biophysical methods-mainly spectroscopy and imaging techniques-to characterize Aβ/Ni(II) interactions in vitro, for different Aβ variants: Aβ(1-40), Aβ(1-40)(H6A, H13A, H14A), Aβ(4-40), and Aβ(1-42). We show for the first time that Ni(II) ions display specific binding to the N-terminal segment of full-length Aβ monomers. Equimolar amounts of Ni(II) ions retard Aβ aggregation and direct it towards non-structured aggregates. The His6, His13, and His14 residues are implicated as binding ligands, and the Ni(II)·Aβ binding affinity is in the low µM range. The redox-active Ni(II) ions induce formation of dityrosine cross-links via redox chemistry, thereby creating covalent Aβ dimers. In aqueous buffer Ni(II) ions promote formation of beta sheet structure in Aβ monomers, while in a membrane-mimicking environment (SDS micelles) coil-coil helix interactions appear to be induced. For SDS-stabilized Aβ oligomers, Ni(II) ions direct the oligomers towards larger sizes and more diverse (heterogeneous) populations. All of these structural rearrangements may be relevant for the Aβ aggregation processes that are involved in AD brain pathology.
This paper proposes a novel in-wheel motor, which artfully integrates a magnetic gear into a permanent-magnet brushless (PMBL) DC motor so that they can share a common PM rotor, hence offering both ...high efficiency and high power density. Moreover, the low-speed requirement for direct driving and the high-speed requirement for compact motor design can be achieved simultaneously. A 2-kW 600/4400-rpm magnetic-geared outer-rotor PMBL DC motor is designed and analyzed, which is particularly suitable for battery-powered electric motorcycles
Solar‐driven interfacial steam generation (SISG) has been recognized as a promising strategy to solve water shortages in an eco‐friendly and low‐cost way. However, the practical application of SISG ...is vitally restricted by some inherent limits, especially for finite evaporation rate and insufficient working life of evaporator. Herein, a novel SISG system involving an all‐fiber porous cylinder‐like foam 3D evaporator, side area‐assisted evaporation protocol, and aggregation‐induced‐emission‐active solar absorber with “one stone two birds” function is explored. The solar absorber exhibits efficient photothermal conversion, endowing the side area‐assisted evaporator with as high as 3.6 kg m−2 h−1 of solar evaporation rate, which is highly desirable for SISG under 1 sun of irradiation. Moreover, the solar absorber is capable of powerfully producing reactive oxygen species upon sunlight irradiation, which results in extraordinary photodynamic killing of bacteria nearby the fiber to prevent biofouling, consequently improving the working life of evaporator.
A solar‐driven interfacial steam generation (SISG) system involving an all‐fiber porous cylinder‐like foam 3D evaporator, side area‐assisted evaporation protocol, and aggregation‐induced‐emission‐active solar absorber is explored. The SISG system exhibits a high solar evaporation rate of 3.6 kg m−2 h−1, and shows photodynamic killing of bacteria to prevent biofouling.
► RTFM in chemically synthesized Ni doped ZnS nanoparticles is reported.. ► Structural analysis shows the cubic structure of Ni doped ZnS nanoparticles. ► X-ray absorption spectroscopy reveals that ...Ni replace the Zn atoms in the host lattice.
Ni doped ZnS (Zn1−xNixS) nanoparticles with Ni concentration x=0.01, 0.03 and 0.05 were synthesized by the chemical co-precipitation technique. Powder X-ray diffraction (XRD) reveals that Ni incorporates into the ZnS crystal lattice with a cubic structure. Transmission electron microscopy (TEM) measurements show that the average size of these nanoparticles is in the range 2–3nm. Micro-Raman and photololuminescence (PL) studies also confirm the incorporation of Ni in the lattice. X-ray absorption spectroscopy (XAS) reveals that Ni replace the Zn atoms in the host lattice without forming second phases. The ZnS nanoparticles with lower Ni concentration exhibit saturated hysteresis loop at room temperature indicating ferromagnetism where as samples having higher Ni concentrations did not show such saturation confirming the intrinsic nature of the ferromagnetism at smaller doping.
Fluorescence‐imaging‐guided photodynamic therapy has emerged as a promising protocol for cancer theranostics. However, facile preparation of such a theranostic material for simultaneously achieving ...bright emission with long wavelength, high‐performance reactive oxygen species (ROS) generation, and good targeting‐specificity of cancer cells, is highly desirable but remains challenging. In this study, a novel type of far‐red/near‐infrared‐emissive fluorescent molecules with aggregation‐induced emission (AIE) characteristics is synthesized through a few steps reaction. These AIE luminogens (AIEgens) possess simple structures, excellent photostabilities, large Stokes shifts, bright emission, and good biocompatibilities. Meanwhile, their ROS generation is extremely efficient with up to 90.7% of ROS quantum yield, which is far superior to that of some popularly used photosensitizers. Importantly, these AIEgens are able to selectively target and ablate cancer cells over normal cells without the aid of any extra targeting ligands. Rather than using laser light, one of the presented AIEgens (MeTTPy) shows a remarkable tumor‐targeting photodynamic therapeutic effect by using an ultralow‐power lamp light (18 mW cm−2). This study thus not only extends the applications scope of AIEgens, but also offers useful insights into designing a new generation of cancer theranostics.
Highly efficient photosensitizers with far‐red/near‐infrared aggregation‐induced emission are facilely synthesized and used for in vitro and in vivo cancer theranostics. These materials are able to selectively target and ablate cancer cells over normal cells without the aid of any extra targeting ligands, and show a remarkable tumor‐targeting photodynamic therapeutic effect by using an ultralow‐power lamp light (18 mW cm−2).
Context.
The Milky Way nuclear star cluster (MWNSC) is a crucial laboratory for studying the galactic nuclei of other galaxies, but its properties have not been determined unambiguously until now.
...Aims.
We aim to study the size and spatial structure of the MWNSC.
Methods.
This study uses data and methods that address potential shortcomings of previous studies on the topic. We use 0.2″ angular resolution
K
s
data to create a stellar density map in the central 86.4 pc × 21 pc at the Galactic center. We include data from selected adaptive-optics-assisted images obtained for the inner parsecs. In addition, we use
Spitzer
/IRAC mid-infrared (MIR) images. We model the Galactic bulge and the nuclear stellar disk in order to subtract them from the MWNSC. Finally, we fit a Sérsic model to the MWNSC and investigate its symmetry.
Results.
Our results are consistent with previous work. The MWNSC is flattened with an axis ratio of
q
= 0.71 ± 0.10, an effective radius of
R
e
= (5.1 ± 1.0) pc, and a Sérsic index of
n
= 2.2 ± 0.7. Its major axis may be tilted out of the Galactic plane by up to −10°. The distribution of the giants brighter than the Red Clump (RC) is found to be significantly flatter than the distribution of the faint stars. We investigate the 3D structure of the central stellar cusp using our results on the MWNSC structure on large scales to constrain the deprojection of the measured stellar surface number density, obtaining a value of the 3D inner power law of
γ
= 1.38 ± 0.06
sys
± 0.01
stat
.
Conclusions.
The MWNSC shares its main properties with other extragalactic NSCs found in spiral galaxies. The differences in the structure between bright giants and RC stars might be related to the existence of not completely mixed populations of different ages. This may hint at recent growth of the MWNSC through star formation or cluster accretion.
The efficient utilization of energy dissipating from non‐radiative excited‐state decay of fluorophores was only rarely reported. Herein, we demonstrate how to boost the energy generation of ...non‐radiative decay and use it for cancer theranostics. A novel compound (TFM) was synthesized which possesses a rotor‐like twisted structure, strong absorption in the far red/near‐infrared region, and it shows aggregation‐induced emission (AIE). Molecular dynamics simulations reveal that the TFM aggregate is in an amorphous form consisting of disordered molecules in a loose packing state, which allows efficient intramolecular motions, and consequently elevates energy dissipation from the pathway of thermal deactivation. These intrinsic features enable TFM nanoparticles (NPs) to display a high photothermal conversion efficiency (51.2 %), an excellent photoacoustic (PA) effect, and effective reactive oxygen species (ROS) generation. In vivo evaluation shows that the TFM NPs are excellent candidates for PA imaging‐guided phototherapy.
No radiation, no problem! A novel AIEgen was synthesized and confirmed to be an excellent platform for elevating energy dissipation from nonradiative decay. This AIEgen has a high photothermal conversion efficiency (51.2 %), an excellent photoacoustic effect and effective reactive oxygen species generation, making it powerful in multi‐modality theranostics for cancer treatment.
We report results from a study of the spin and parity of Ξ c ( 2970 ) + using a 980 fb −1 data sample collected by the Belle detector at the KEKB asymmetric-energy e+e− collider. The decay angle ...distributions in the chain Ξc (2970)+→ Ξc (2645) 0π+ → Ξ+c π− π+ are analyzed to determine the spin of this charmed-strange baryon. The angular distributions strongly favor the Ξc (2970)+ spin J = 1/2 over 3/2 or 5/2, under an assumption that the lowest partial wave dominates in the decay. We also measure the ratio of Ξc (2970)+ decay branching fractions R = B Ξc (2970)+ → Ξc (2645)0π+/B Ξc (2970)+ → Ξ0c π+ = 1.67 ± 0.29 (stat)+0.15 −0.09 (syst) ± 0.25 (IS), where the last uncertainty is due to possible isospin-symmetry-breaking effects. This R value favors the spin-parity J P = 1/2+ with the spin of the light-quark degrees of freedom sl = 0. This is the first determination of the spin and parity of a charmed-strange baryon.
Photodynamic therapy (PDT) has long been shown to be a powerful therapeutic modality for cancer. However, PDT is undiversified and has become stereotyped in recent years. Exploration of distinctive ...PDT methods is thus highly in demand but remains a severe challenge. Herein, an unprecedented 1+1+1>3 synergistic strategy is proposed and validated for the first time. Three homologous luminogens with aggregation‐induced emission (AIE) characteristics were rationally designed based on a simple backbone. Through slight structural tuning, these far‐red/near‐infrared AIE luminogens are capable of specifically anchoring to mitochondria, cell membrane, and lysosome, and effectively generating reactive oxygen species (ROS). Notably, biological studies demonstrated combined usage of three AIE photosensitizers gives multiple ROS sources simultaneously derived from several organelles, which gives superior therapeutic effect than that from a single organelle at the same photosensitizers concentration. This strategy is conceptually and operationally simple, providing an innovative approach and renewed awareness of improving therapeutic effect through three‐pronged PDT.
Power of three: A synergistic enhanced photodynamic therapy (PDT) strategy was developed that concurrently acts on multiple subcellular organelles. At the same photosensitizer concentration, combined PDT treatment with three aggregation‐induced emission luminogens (AIEgens) exhibits superior therapeutic effect than that of single AIEgens.
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