Polyelectrolyte multilayer (PEM) capsules are promising candidates for many kinds of cancer detection and treatment but are usually intended to deliver cargo to specific sites or to destroy cancer ...cells based on photothermal effects from the outside. In this publication we prove that it is possible to kill cancer cells from the inside based on phagocytosed PEM capsules. In addition we show how to open the cells and bring the PEM capsules to the surface of cancer cells based on photothermal effects and rapid evaporation of water. Diffusion-based temperature determinations of the photothermal effect up to the evaporation temperature of water are presented.
Oxygen evolution reaction (OER) is a pivotal process in many energy conversion and storage techniques, such as water splitting, regenerative fuel cells, and rechargeable metal-air batteries. The ...synthesis of stable, efficient, non-noble metal-based electrocatalysts for OER has been a long-standing challenge. In this work, a facile and scalable method to synthesize hollow and conductive iron–cobalt phosphide (Fe–Co–P) alloy nanostructures using an Fe–Co metal organic complex as a precursor is described. The Fe–Co–P alloy exhibits excellent OER activity with a specific current density of 10 mA/cm2 being achieved at an overpotential as low as 252 mV. The current density at 1.5 V (vs reversible hydrogen electrode) of the Fe–Co–P catalyst is 30.7 mA/cm2, which is more than 3 orders of magnitude greater than that obtained with state-of-the-art Fe–Co oxide catalysts. Our mechanistic experiments and theoretical analysis suggest that the electrochemical-induced high-valent iron stabilizes the cobalt in a low-valent state, leading to the simultaneous enhancement of activity and stability of the OER catalyst.
The design of efficient catalysts capable of delivering high currents at low overpotentials for hydrogen evolution reactions (HERs) is urgently needed to use catalysts in practical applications. ...Herein, we report platinum (Pt) alloyed with titanium (Ti) from the surface of Ti3C2T x MXenes to form Pt3Ti intermetallic compound (IMC) nanoparticles (NPs) via in situ coreduction. In situ X-ray absorption spectroscopy (XAS) indicates that Pt undergoes a temperature-dependent transformation from single atoms to intermetallic compounds, and the catalyst reduced at 550 °C exhibits a superior HER performance in acidic media. The Pt/Ti3C2T x -550 catalyst outperforms commercial Pt/Vulcan and has a small overpotential of 32.7 mV at 10 mA cm–2 and a low Tafel slope of 32.3 mV dec–1. The HER current was normalized by the mass and dispersion of Pt, and the mass activity and specific activity of Pt/Ti3C2T x -550 are 4.4 and 13 times higher, respectively, than those of Pt/Vulcan at an overpotential of 70 mV. The density functional theory (DFT) calculations suggest that the (111)- and (100)-terminated Pt3Ti nanoparticles exhibit *H binding comparable to Pt(111), while the (110) termination has an *H adsorption that is too exergonic, thus poisoned in the low overpotential region. This work demonstrates the potential of MXenes as platforms for the design of electrocatalysts and may spur future research for other MXene-supported metal catalysts that can be used for a wide range of electrocatalytic reactions.
Supported nanoparticles are broadly employed in industrial catalytic processes, where the active sites can be tuned by metal-support interactions (MSIs). Although it is well accepted that supports ...can modify the chemistry of metal nanoparticles, systematic utilization of MSIs for achieving desired catalytic performance is still challenging. The developments of supports with appropriate chemical properties and identification of the resulting active sites are the main barriers. Here, we develop two-dimensional transition metal carbides (MXenes) supported platinum as efficient catalysts for light alkane dehydrogenations. Ordered Pt
Ti and surface Pt
Nb intermetallic compound nanoparticles are formed via reactive metal-support interactions on Pt/Ti
C
T
and Pt/Nb
CT
catalysts, respectively. MXene supports modulate the nature of the active sites, making them highly selective toward C-H activation. Such exploitation of the MSIs makes MXenes promising platforms with versatile chemical reactivity and tunability for facile design of supported intermetallic nanoparticles over a wide range of compositions and structures.
Due to their rapid development and wide application in modern agriculture, robots, mobile terminals, and intelligent devices have become vital technologies and fundamental research topics for the ...development of intelligent and precision agriculture. Accurate and efficient target detection technology is required for mobile inspection terminals, picking robots, and intelligent sorting equipment in tomato production and management in plant factories. However, due to the limitations of computer power, storage capacity, and the complexity of the plant factory (PF) environment, the precision of small-target detection for tomatoes in real-world applications is inadequate. Therefore, we propose an improved Small MobileNet YOLOv5 (SM-YOLOv5) detection algorithm and model based on YOLOv5 for target detection by tomato-picking robots in plant factories. Firstly, MobileNetV3-Large was used as the backbone network to make the model structure lightweight and improve its running performance. Secondly, a small-target detection layer was added to improve the accuracy of small-target detection for tomatoes. The constructed PF tomato dataset was used for training. Compared with the YOLOv5 baseline model, the mAP of the improved SM-YOLOv5 model was increased by 1.4%, reaching 98.8%. The model size was only 6.33 MB, which was 42.48% that of YOLOv5, and it required only 7.6 GFLOPs, which was half that required by YOLOv5. The experiment showed that the improved SM-YOLOv5 model had a precision of 97.8% and a recall rate of 96.7%. The model is lightweight and has excellent detection performance, and so it can meet the real-time detection requirements of tomato-picking robots in plant factories.
Supported multimetallic nanoparticles (NPs) are widely used in industrial catalytic processes, where the relation between surface structure and function is well-known. However, the effect of ...subsurface layers on such catalysts remains mostly unstudied. Here, we demonstrate a clear subsurface effect on supported 2 nm core–shell NPs with atomically precise and high temperature stable Pt3Mn intermetallic surface measured by in situ synchrotron X-ray Diffraction, difference X-ray Absorption Spectroscopy, and Energy Dispersive X-ray Spectroscopy. The NPs with a Pt3Mn subsurface have 98% selectivity to C–H over C–C bond activation during propane dehydrogenation at 550 °C compared with 82% for core–shell NPs with a Pt subsurface. The difference is correlated with significant reduction in the heats of reactant adsorption due to the Pt3Mn intermetallic subsurface as discerned by theory as well as experiment. The findings of this work highlight the importance of subsurface for supported NP catalysts, which can be tuned via controlled intermetallic formation. Such approach is generally applicable to modifying multimetallic NPs, adding another dimension to the tunability of their catalytic performance.
Geometric structure of Pt and Pt–In catalysts and crystal structures of the active phase.▪
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•Pt3In and PtIn2 alloys have much high selectivity for ethane dehydrogenation than ...Pt.•Geometric isolation of Pt sites are suggested to be responsible for high olefin dehydrogenation selectivity.•In promotes the turnover rate of Pt and the promotion depends on the specific alloy structure.
The structure of silica supported Pt and Pt–In bimetallic catalysts with nominal In:Pt atomic ratios of 0.7 and 1.4 were determined by in situ synchrotron XAS and XRD. It was seen that the addition of In led to the formation of two different intermetallic alloy phases. At an In:Pt ratio of 0.7 the Pt3In phase with a Cu3Au structure was formed. When the ratio was increased to 1.4 a shell of PtIn2 having a CaF2 structure formed around a core of Pt3In. The catalysts were tested for ethane dehydrogenation at 600°C to determine the effect of alloying on ethylene selectivity and turnover rate (TOR). The monometallic Pt catalysts was 73% selective for ethylene and had an initial TOR of 0.7s−1. Both alloy catalysts were ≈100% selective for dehydrogenation and had higher initial TOR, 2.8s−1 and 1.6s−1 for In:Pt ratio of 0.7 and 1.4, respectively. The increase in selectivity is attributed to the elimination of large Pt ensembles resulting from geometric changes to the catalyst surface upon alloying. Electronic changes due to the formation of Pt–In bonds are thought to be responsible for the increases in TOR in the alloy catalysts.
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•A new class of BRD4 degraders were designed and synthesized.•All synthesized compounds were evaluated for their ability to inhibit BRD4.•Cell proliferation inhibition was assessed in ...the HL-60, Raji and THP-1 cell lines.•Compound 21 effectively induced the degradation of BRD4 protein and suppression of c-Myc expression.
BRD4 has emerged as an attractive target for anticancer therapy. However, BRD4 inhibitors treatment leads to BRD4 protein accumulation, together with the reversible nature of inhibitors binding to BRD4, which may limit the efficacy of BRD4 inhibitors. To address these problems, a protein degradation strategy based on the proteolysis targeting chimera (PROTAC) technology has been developed to target BRD4 recently. Herein, we present our design, synthesis and biological evaluation of a new class of PROTAC BRD4 degraders, which were based on a potent dihydroquinazolinone-based BRD4 inhibitor compound 6 and lenalidomide/pomalidomide as ligand for E3 ligase cereblon. Gratifyingly, several compounds showed excellent inhibitory activity against BRD4, and high anti-proliferative potency against human monocyte lymphoma cell line THP-1. Especially, compound 21 (BRD4 BD1, IC50 = 41.8 nM) achieved a submicromolar IC50 value of 0.81 μM in inhibiting the growth of THP-1 cell line, and was 4 times more potent than compound 6. Moreover, the mechanism study established that 21 could effectively induce the degradation of BRD4 protein and suppression of c-Myc. All of these results suggested that 21 was an efficacious BRD4 degrader for further investigation.
To date, research on the physical and mechanical behavior of nickel-titanium shape-memory alloy (NiTi SMA) has focused on the macroscopic physical properties, equation of state, strength ...constitution, phase transition induced by temperature and stress under static load, etc. The behavior of a NiTi SMA under high-strain-rate impact and the influence of voids have not been reported. In this present work, the behavior evolution of (100) single-crystal NiTi SMA and the influencing characteristics of voids under a shock wave of 1.2 km/s are studied by large-scale molecular dynamics calculation. The results show that only a small amount of B2 austenite is transformed into B19’ martensite when the NiTi sample does not pass through the void during impact compression, whereas when the shock wave passes through the hole, a large amount of martensite phase transformation and plastic deformation is induced around the hole; the existence of phase transformation and phase-transformation-induced plastic deformation greatly consumes the energy of the shock wave, thus making the width of the wave front in the subsequent propagation process wider and the peak of the foremost wave peak reduced. In addition, the existence of holes disrupts the orderly propagation of shock waves, changes the shock wave front from a plane to a concave surface, and reduces the propagation speed of shock waves. The calculation results show that the presence of pores in a porous NiTi SMA leads to significant martensitic phase transformation and plastic deformation induced by phase transformation, which has a significant buffering effect on shock waves. The results of this study provide great guidance for expanding the application of NiTi SMA in the field of shock.
Vanadium catalysts offer unique selectivity in olefin polymerization, yet are underutilized industrially owing to their poor stability and productivity. Reported here is the immobilization of ...vanadium by cation exchange in MFU‐4l, thus providing a metal–organic framework (MOF) with vanadium in a molecule‐like coordination environment. This material forms a single‐site heterogeneous catalyst with methylaluminoxane and provides polyethylene with low polydispersity (PDI≈3) and the highest activity (up to 148 000 h−1) reported for a MOF‐based polymerization catalyst. Furthermore, polyethylene is obtained as a free‐flowing powder as desired industrially. Finally, the catalyst shows good structural integrity and retains polymerization activity for over 24 hours, both promising attributes for the commercialization of vanadium‐based polyolefins.
Caught in a MOF: Vanadium catalysts show coveted selectivity in olefin polymerization, but suffer from poor stability and productivity. Incorporation of vanadium into a metal–organic framework provided a single‐site heterogeneous catalyst with exceptional activity and stability for ethylene polymerization. X‐ray absorption spectroscopy analysis indicates a discrete, molecule‐like coordination of V4+ cations within this material. MMAO‐12=modified methylaluminoxane‐12.
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