Search

Mn-Zn ferrites with high initial permeability ( μ ) and high saturation magnetic flux density ( B ) were successfully synthesized by using a conventional ceramic processing route with addition of MoO. The structure, morphology, magnetic properties, and complex impedance of all samples were investigated by X-ray diffraction, scanning electron microscopy, DC magnetic instrument, and precision LCR meter. The addition of MoO promotes the growth of larger and more uniform grains and therefore enhances the μ . Meanwhile, it improves the density and hence the B . Through the analysis of complex impedance spectra by an equivalent circuit model, it is demonstrated that MoO mainly exists at grain boundaries and improves the impedance in a wide frequency range. [ABSTRACT FROM AUTHOR]

The SiO2 coated sphere and flaky carbonyl iron powders (CIPs) heterogeneous nanocomposites have been prepared through the Stöber method and subsequently, through an annealing process for eliminating the crystal defect and enhancing the insulation and oxidation resistance of SiO2 shell. The CIP@SiO2 heterogeneous nanocomposites were characterized by X-ray diffraction (XRD), Fourier Transform infrared (FTIR) spectroscopy, Scanning Electron Microscopy (SEM), Thermogravimetric (TG) analysis and Vector Network Analyzer (VNA). The CIP surface had been successfully assembly-coated with nano SiO2 layer, obtained by the SEM, XRD, and FTIR. Both the annealing treatment and the SiO2 shell can synergetically improve the oxidation resistance property due to the reduction of defects and residual stress, and isolation of oxygen, respectively. Changed everywhere permittivity (magnetic permeability) by effective permittivity (magnetic permeability). The real part of the permittivity of the nanocomposite decreased significantly, while the imaginary part of permittivity remained the same indicating the increase of dielectric loss. The permeability decreased slightly for the SiO2 insulated shell blocking the magnetic path. Hence, the electromagnetic match property was greatly improved by coating SiO2 insulated shell, and this composite showed a broad absorption band. [ABSTRACT FROM AUTHOR]

Abstract: Monodispersed magnetic MFe2O4 (M=Fe, Co) hollow spheres were synthesized by simple template free solvothermal method in ethylene glycol (EG) solution. The hollow spheres were in the same size with an average diameter of about 360nm and the shells of these spheres were about 80nm, consisted of closely packed nanocrystallines due to Ostwald ripening. EG plays the key role in the synthesis of hollow spheres in contrast with octahedral crystals synthesized in aqueous solution. The products synthesized in aqueous solution were calcined at 800°C and 1000°C. The amount of spinel ferrite products increased monotonically with the increase of temperature and appeared as a single phase at 1000°C. The saturation magnetization (M s), remanent magnetization (M r) and coercivity (H c) for Fe3O4 hollow spheres was 74.47emu/g, 2.59emu/g and 32.503Oe respectively whereas the reading of the same indicators for CoFe2O4 hollow spheres was 69.07emu/g, 14.46emu/g and 242.79Oe, respectively. The magnetic variation between Fe3O4 and CoFe2O4 hollow spheres was caused by the radius difference of Fe2+ (3d6) and Co2+ (3d7) ions and it was also relevant with nanocrystal sizes of the spin disorder of crystal surface. [Copyright &y& Elsevier]

In ceramic injection molding, the conventional solvent‐debinding process encounters limitations such as solvent cost and environmental pollution. In this paper, a suitable thermal‐debinding process from room temperature to 250°C using carbon/alumina embedding powders with nano and submicron size was developed to remove the soluble binders replacing the conventional solvent debinding of injection molding ZrO2 ceramic. The effects of the embedding powders on microstructure and debinding ratio were studied in detail. The results showed that the main factor influencing debinding ratio was associated with the sufficient dispersing of mixed particles, which was characterized by the relative change ratio of tap volume. A debinding mechanism was proposed to explain the effects of carbon/alumina mixed powders on the debinding ratio and surface cracks. Based on the influencing mechanism, the debinded green part with the elimination of soluble binders and optimal surface was achieved using the mixed powders with C/A = 8/2 on the top and C/A = 4/6 on the bottom. [ABSTRACT FROM AUTHOR]

2-Mercaptoethanol (2-ME) is often used as an antioxidant to optimize culture systems for in vitro oocyte maturation in livestock. However, the relationship between 2-ME and autophagy has not yet been elucidated. In this study, we hypothesized that 2-ME can promote porcine oocyte maturation in vitro by maintaining autophagy homeostasis. To test this hypothesis, we explored the effects of 2-ME on the maturation of porcine oocytes exposed to an autophagy activator (rapamycin) or an autophagy inhibitor (3-methyladenine, i.e., 3-MA) in vitro. Rapamycin-induced autophagy over-activation significantly increased autophagy- and apoptosis-related gene expression, oxidative stress, apoptosis rates, abnormal mitochondrial redistribution, and significantly decreased oocyte first polar body extrusion (PBE) rates, spindle/chromosome integrity and developmental competence. 3-MA-mediated autophagy inhibition exerted similar effects on all these parameters except the expression of genes that promote autophagy and inhibit apoptosis. Importantly, 2-ME supplementation significantly attenuated the detrimental effects of rapamycin and 3-MA. Interestingly, we observed that 44 h of coincubation with rapamycin/3-MA and 2-ME restored autophagy homeostasis in vitro. In conclusion, our study confirmed that 2-ME promotes porcine oocyte maturation and embryo development in vitro by maintaining autophagy homeostasis and lays a foundation for further research on the underlying mechanism. • 2- mercaptoethanol can alleviate the damage of porcine oocyte maturation caused by inhibited autophagy. • 2- mercaptoethanol can alleviate the damage of porcine oocyte maturation caused by over-activated autophagy. • 2-mercaptoethanol can promote porcine oocyte maturation in vitro by maintaining autophagy homeostasis. [ABSTRACT FROM AUTHOR]

Polyvinyl butyral (PVB) was used in the Al(OH)3/carbon black/ethanol slurries by the three-roll mixing to prepare AlN powder using the carbothermal reduction–nitridation (CRN) process in the experiments. The effects of PVB addition on the synthesis of AlN powder were studied by viscosity, tap density, XRD, SEM and TG measurements. The results showed that the PVB layer covering on the surface of Al(OH)3 particles reduced the viscosity of Al(OH)3/carbon/ethanol slurry and increased the dispersion homogeneity of Al(OH)3/carbon raw powder. The tap densities of the Al(OH)3/carbon mixtures after three-roll milling could be increased with the increase in PVB addition. In the CRN process, most of the PVB covering Al(OH)3 particles evaporated and supplied the passage for nitrogen removal to the particles. Based on the experimental data, the role of PVB on the mixing and CRN process was discussed. [ABSTRACT FROM AUTHOR]

Lipopolysaccharide (LPS), the main virulence factor of gram-negative bacteria, severely impairs the function of the female reproductive system. It has especially harmful effects on oocytes and subsequent embryonic development. The use of active plant substances to ameliorate the damage caused by LPS exposure is a strategy worthy of attention. In this study, porcine oocytes were used to investigate the protective effects and underlying mechanisms of allicin, an extract derived from garlic, on LPS-exposed oocytes in vitro. Our data indicated that supplementation with 1 μM allicin significantly attenuated the LPS-mediated reductions in the first polar body extrusion rate and the subsequent blastocyst formation rate. Allicin also mitigated the abnormalities in spindle assembly, chromosome alignment, actin polymerization, and cortical granule distribution caused by LPS exposure. Furthermore, allicin restored reactive oxygen species (ROS), early apoptosis and autophagy to normal physiological levels in LPS-exposed oocytes. In conclusion, our findings confirm that allicin can protect oocytes against LPS-induced damage. The results of this study will help promote the application of plant-derived bioactive substances to ameliorate oocyte maturation defects. • Allicin had protective effects against LPS induced nuclear and cytoplasmic maturation defects in oocytes cultured in vitro. • Allicin could restore ROS, early apoptosis and autophagy to a normal physiological level in LPS-exposed oocytes. • Allicin had ameliorative effects on early embryonic development of LPS-exposed oocytes. [ABSTRACT FROM AUTHOR]

Herein, flake-like FeSiAl particles are prepared by rapid quenching and subsequent ball milling processes. Then, soft magnetic composites are fabricated by orderly aligned flake-like FeSiAl particles, resulting in the formation of nacre-like structure. The influence of processing parameters on columnar microstructure of the thin strips has been studied in detail. Furthermore, the magnetic permeability and loss of the soft magnetic composites, with different compositions, are explored. The results reveal that the soft magnetic composite, with flake-like Fe 85 Si 9.6 Al 5.4 , renders the magnetic permeability of 200 at 1 MHz, which is much higher than the spherical FeSiAl particles. Moreover, the negative temperature-dependent loss and a valley temperature of 65 °C are observed at the Sendust composition of Fe 85 Si 8.8 Al 6.2 , which maintained the magnetic permeability of 172 at 1 MHz and a loss of 380 kW/m3 at 50 kHz (stimulated at 100 mT). It is worth emphasizing that the nacre-like SMC exhibits outstanding properties and renders promise for next-generation magnetic devices. • The soft magnetic composites are fabricated by orderly aligned flake-like FeSiAl particles which was prepared by rapid quenching, resulting in the formation of nacre-like structure, renders the magnetic permeability of 200 at 1 MHz, which is much higher than the spherical FeSiAl particles. [ABSTRACT FROM AUTHOR]

Self‐monitoring in tumor therapy is a concept that allows for real‐time monitoring of the location and state of applied nanomaterials. This monitoring relies on dynamic signals, such as wave or magnetic signals, which vary in response to changes in the location and state of nanomaterials. Dynamic changes in nanomaterials can be monitored using dynamic signals, making it possible to determine and control the treatment process. Theranostic nanomaterials, which possess unique physical and chemical properties, have recently been explored as a viable option for self‐monitoring. With the help of self‐monitoring, theranostic nanomaterials can guide themselves to achieve region‐selective treatment with higher controllability and safety. In this review, self‐monitoring theranostic nanomaterials will be introduced in three parts according to their roles during therapy: tumor accumulation, tumor therapy, and metabolism. The limitations and future challenges of current self‐monitoring theranostic nanomaterials will also be discussed. [ABSTRACT FROM AUTHOR]

Skeletal muscle myogenesis hinges on gene regulation, meticulously orchestrated by molecular mechanisms. While the roles of transcription factors and non-coding RNAs in myogenesis are widely known, the contribution of RNA-binding proteins (RBPs) has remained unclear until now. Therefore, to investigate the functions of post-transcriptional regulators in myogenesis and uncover new functional RBPs regulating myogenesis, we employed CRISPR high-throughput RBP-KO (RBP-wide knockout) library screening. Through this approach, we successfully identified Eef1a1 as a novel regulatory factor in myogenesis. Using CRISPR knockout (CRISPRko) and CRISPR interference (CRISPRi) technologies, we successfully established cellular models for both CRISPRko and CRISPRi. Our findings demonstrated that Eef1a1 plays a crucial role in promoting proliferation in C2C12 myoblasts. Through siRNA inhibition and overexpression methods, we further elucidated the involvement of Eef1a1 in promoting proliferation and suppressing differentiation processes. RIP (RNA immunoprecipitation), miRNA pull-down, and Dual-luciferase reporter assays confirmed that miR-133a-3p targets Eef1a1. Co-transfection experiments indicated that miR-133a-3p can rescue the effect of Eef1a1 on C2C12 myoblasts. In summary, our study utilized CRISPR library high-throughput screening to unveil a novel RBP, Eef1a1, involved in regulating myogenesis. Eef1a1 promotes the proliferation of myoblasts while inhibiting the differentiation process. Additionally, it acts as an antagonist to miR-133a-3p, thus modulating the process of myogenesis. [ABSTRACT FROM AUTHOR]

With the development of switching power supply and electronic technology, the demand for portable electronics is constantly moving towards miniaturization, high-frequency, and low-power loss. This demand has put forward new requirements and challenges for the performance of multilayer chip power inductor. FeSiCr iron-based soft magnetic materials are widely used in the preparation of high-quality multilayer chip power inductor due to their higher magnetic permeability, quality factor Q, and oxidation resistance. However, the sintering conditions of the FeSiCr material have a significant impact on the performance of the multilayer chip power inductor. Currently, few of the reported study have considered the influence of oxygen partial pressure on the performance of multilayer alloy chip power inductor during sintering process. This paper studied the influencing factors of atmosphere sintering pretreatment temperature and time, sintering temperature and oxygen partial pressure during sintering process, based on the multilayer chip power inductor with the size of 201610. The formation mechanism of the influence curves has been comprehensively analyzed theoretically, and Maxwell FEM simulation was used to obtain the magnetic density distribution of the inductor. Finally, the best sintering conditions of the FeSiCr multilayer chip power inductor have been found. According to the comparative experimental under different sintering conditions, the following conclusions can been obtained: the appropriate adhesive discharge temperature and time are 350℃ and 60 minutes, respectively, the optimal sintering temperature is around 750 ℃, the optimal temperature rise rate is 5℃/min. While the oxygen partial pressure is about 6.5%, the multilayer inductor can obtain excellent electrical properties. [ABSTRACT FROM AUTHOR]

SrFe 12 O 19 is widely used due to its low cost, stability and corrosion resistance. In this study, Sm-doped porous SrFe 12 O 19 powder with high coercivity was synthesized using KCl- assisted spray pyrolysis. The Sm doping, microstructure and magnetic properties were studied by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM) and vibrating sample magnetometer (VSM). The results showed that when Sm-doping amount was 0.2, the ferrite powder prepared by KCl-assisted spray pyrolysis had high coercivity of 7.286 kOe and saturation magnetization of 56.422 emu/g. The coercivity of the Sm-doped samples increased by 39.23 % compared with that of the undoped samples. The significant increase in coercivity was associated with the improvement of super-exchange interaction between Fe3+ particles caused by Sm doping, and the size decrease of the hexagonal plate Sr-ferrite particle caused by KCl action. The influencing mechanism of coercivity was discussed in detail based on the analysis of crystal structure and microstructure observation. [ABSTRACT FROM AUTHOR]

FeSiCr/Al 2 O 3 modified powders were prepared by dry milling and coupling for different durations, and FeSiCr/Al 2 O 3 epoxy resin composites were prepared by banburying and low-pressure molding. The melt index, bending strength, magnetic permeability, and magnetic loss of the FeSiCr/Al 2 O 3 epoxy resin composites were measured. The microstructures of the different FeSiCr/Al 2 O 3 modified powders and FeSiCr/Al 2 O 3 epoxy resin composites were observed using scanning electron microscopy (SEM), and their effects on the flowability, magnetic, and mechanical properties of the composites are discussed. The results showed that dry milling and coupling modification greatly improved the flowability of the FeSiCr/Al 2 O 3 /epoxy resin composites. Moreover, the bending strength and effective magnetic permeability increased, and the core loss decreased. Based on the loss data, a new loss separation method that is different from the conventional low-frequency method is proposed. Residual, hysteresis, and eddy current loss were in descending order in the frequency range of 100–2000 kHz. [ABSTRACT FROM AUTHOR]

In this study, aluminium nitride (AlN) powder was prepared by the carbothermal reduction–nitridation method using ultrafine alumina and carbon black as the raw materials. A polyethylene glycol (PEG) and emulsifier (OP-10) disperse system was used to distribute the raw powders during ball milling. The mixing slurries and as-received AlN products were investigated using a viscometer, X-ray diffraction, field emission scanning electron microscopy, oxygen nitrogen hydrogen analyser, TG analysis and a laser particle size analyser. The results showed that the OP-10/PEG composite system reduced the viscosity of the slurry containing alumina and carbon during ball milling and significantly improved the wettability of water on the carbon black powder. The viscosity decrease improved the distribution of alumina and carbon under the same ball-milling conditions. At the same time, a dispersed structure was formed in which the OP-10 micelles separated alumina particles with carbon particles. Furthermore, the micelles with carbon were separated by the long PEG chains. This increased the number of primary particles below 2 μm and decreased the number of agglomerates above 5 μm in the final CRN AlN products. Based on the experimental results, herein the dispersion mechanism of the OP-10/PEG composite system on fine alumina and carbon black is proposed. Moreover, the rationality of the composite system is discussed. [ABSTRACT FROM AUTHOR]

Breast cancer is one of the deadliest cancers for women, so cell labeling and therapy of breast cancer become imperative. In this work, dextran- and carboxymethyl dextran–coated Fe3O4 nanoparticles (Fe3O4@DEX and Fe3O4@CMD) were well synthesized through the co-precipitation method. The dextran and carboxymethyl dextran coating reduces the average particle size of Fe3O4 nanoparticles from 10.9 to 4.0–5.5 nm, and the coated samples exhibit average hydrodynamic diameters ranging from 31 to 110 nm. The coating promotes the dispersibility of nanoparticles. Saturation magnetization is reduced from 60.3 to 5.6–7.1 emu/g in the coated MNPs due to the large weight ratio of the coating layer and the decrease in particle size. Hemolysis and cytotoxicity assay results indicate the excellent biocompatibility of Fe3O4 nanoparticles. The cellular uptake assay confirms that both dextran- and carboxymethyl dextran–coated Fe3O4 nanoparticles are easily taken in by breast cancer cells. Comprehensively considering dispersion, biocompatibility, and cellular uptake, the Fe3O4@CMD is more suitable for application in the bio-labeling of breast cancer cells. The SAR values of the Fe3O4@DEX and Fe3O4@CMD range from 19.2 to 30.7 W/g. The SAR value is mainly influenced by the hydrodynamic diameter in the coated samples. The Fe3O4@CMD20 shows the maximum SAR value of 30.7 W/g and has potential application in magnetic hyperthermia therapy. [ABSTRACT FROM AUTHOR]

In this work, the low-power-loss Mn–Zn ferrite was prepared by the traditional ceramic sintering process. This sample shows the good wide-temperature stability of power loss (P cv). In the whole measurement temperature range of 25 - 120 °C, P cv s maintain less than 100, 682, and 1455 kW/m3 at 100 kHz/100 mT, 500 kHz/100 mT and 800 kHz/100 mT, respectively. The effect of uniaxial compressive stress on power loss at 100, 500 and 800 kHz was investigated. Stress has greater impact on P cv at high frequencies and P cv increases remarkably. To clarify the mechanism of stress on power loss, P cv was divided into three parts including hysteresis loss (P hv), eddy current loss (P ev) and residual loss (P rv), and the effect of stress on each part of loss was discussed. At the low frequency of 100 kHz, P cv is mainly contributed by P hv. The applied stress leads the local anisotropic stress and makes domain wall displacement more difficult, which is the reason of the increase of P hv. When frequency increases to 500 and 800 kHz, P ev and P rv become more important. The compressive stress is in favour of electron transfer between Fe3+ and Fe2+ in grains and electron tunnelling effect at grain boundaries, which leads to the decrease of resistivity. This is the origin of enhanced P ev under the compressive stress. The enhanced P rv is related to the enhanced electronic diffusion under the compressive stress. The clarification of the mechanism of stress on power loss is beneficial to develop new soft ferrite materials with low stress sensitivity for high-frequency applications. [ABSTRACT FROM AUTHOR]

In this work, the P-doped FePt films were successfully prepared by electrodeposition and subsequent annealing. Varied NaH2PO2•H2O was added to adjust the content of P in the FePtP film. Crystalline structure, morphologies in micro- and nano-scales, and magnetic property of FePtP films were investigated. The P doping significantly enhances the coercivity in the FePtP films. High coercivity of 23.8 kOe is achieved in the FePtP film with 22 at% P. The P doping promotes the formation of L10 FePt phase. Nonmagnetic Fe2P and PtP2 are formed by the P doping and segregate at grain boundary, which reduces the exchange coupling between magnetic particles. These two factors result in the enhancement of coercivity. [ABSTRACT FROM AUTHOR]

• A low temperature sintering process with the aid of sintering additive was developed to prepare fine-grain Mn-Zn ferrites. • Mn-Zn ferrite with low power loss and good wide-temperature stability was successfully prepared for the MHz application. • The effect of LiBO 2 sintering aid on magnetic properties of Mn-Zn ferrites was discussed. The low power loss Mn-Zn ferrites with fine grains were developed by the low-temperature-sintering ceramic process for power applications at a high frequency of 1 MHz. The LiBO 2 sintering aid was added to promote the low temperature sintering and densification. The effects of LiBO 2 on micromorphology and magnetic properties of the sintered Mn-Zn ferrites were investigated. With the aid of LiBO 2 , sintering temperature could be reduced as low as 990 °C. The optimum sample was obtained by the addition of 500 ppm LiBO 2 sintered at 1020 °C. The average grain size of this sample is 2.78 μm, the density reaches 4.82 g/cm3, and the minimum power loss is 310 kW/m3 at 1 MHz/30 m T and 25 °C. This sample shows good wide-temperature stability of power loss. The mechanism of power loss affected by the LiBO 2 addition was also discussed. The ceramic sintering process combining the low temperature sintering and the sintering aid offers a new way to develop high-frequency Mn-Zn ferrites. [ABSTRACT FROM AUTHOR]

Due to the rapid development of electronic devices towards high frequency, miniaturization, and high efficiency, it is imperative to develop MHz-frequency power ferrites exhibiting low loss over a broad temperature range. In this work, the broad-temperature low-loss Mn-Zn power ferrites operating in the frequency range of 0.5-3 MHz have been fabricated following the traditional oxide ceramic process. Co 3 O 4 was added and its content was optimized to achieve the broad-temperature characteristics of power loss. The optimal Co 3 O 4 content was determined to be 0.35 wt%. The power losses of this material are less than 30, 120, and 30 kW/m3 in the broad temperature range from 0 to 120 °C under the conditions of 500kHz/50 mT, 1MHz/50 mT, and 3MHz/10 mT, respectively. This material is an ideal material for applications in power conversion electronics at high frequencies (0.5-3 MHz). The effect of Co 3 O 4 addition on power loss is discussed based on the compensation model of magnetocrystalline anisotropy constant. Analysis of the three parts of power loss reveals that the residual loss gradually becomes to be predominant above 1.2 MHz. The addition of Co 3 O 4 reduces the residual loss and increases the cut-off frequency. This is ascribed to the induced uniaxial anisotropy of Co2+. [ABSTRACT FROM AUTHOR]

R -curve and traction-separation relation are commonly used to characterize the fiber bridging, which is significant toughening mechanism in composite laminates. Current investigations are mainly focused on unidirectional laminates. However, the dependence of the R -curve and traction-separation relation on the stacking sequence is still lack of comprehensive studies. Here, the effect of stacking sequence on the R -curve and traction-separation relation in unidirectional and multidirectional CFRP DCB laminates with designed generic +θ°/−θ° and 0°/θ° interfaces were systematically investigated, and interpreted combining with the fractographical analysis of failed fracture surface. Experimental results showed the fiber bridging length, steady-state fracture toughness and maximum bridging stress were strongly influenced by the stacking sequence. However, there was no clear relationship between them and the stacking sequence. In addition, the maximum bridging stress increased with the flexural modulus while a reverse trend presented in the relation between the maximum COD at the end of the fiber bridging zone and the flexural modulus. The obtained traction-separation relations were finally integrated into a tri-linear cohesive zone model. Numerical results from this model agreed well with the test results, which illustrated that the proposed cohesive zone model was applicable for delamination modelling in composite laminates with the effect of fiber bridging. [ABSTRACT FROM AUTHOR]

• Co 2 Z/BaM hexagonal ferrite composite material has low magnetic loss and can be applied in the UHF frequency range. • The external magnetic field provided by the magnetised BaM is used to orient the magnetic moment of Co2Z. • The in-plane anisotropy field, damping coefficient, and magnetization-induced effective external field can be obtained by fitting the magnetic spectra. • Magnetisation increases the energy in the composite material, which corresponds to an increase in the anisotropic field and an increase in the magnetic quality factor. The phase composition, microscopic morphology, magnetic properties, and dielectric properties of composite ferrites consisting of (1-x) Ba 2.8 Bi 0.2 Co 2.2 Fe 22.6 Al 1.2 O 41 (Z) and x BaFe 12 O 19 (BaM) with x = 5,10,20,40 wt% were investigated before and after magnetization. To magnetize the composite ferrite, a soft magnetic phase was combined with a permanent magnetic phase, and the magnetic moment of the former was oriented by the applied magnetic field provided by the latter. The XRD and SEM analyses revealed that the grain size of the composite ferrite was around 1 μm. The actual percentage of BaM phase was higher, which had a diluting effect on the magnetic permeability of the composite ferrites. However, the saturation magnetization strength and coercivity increased with the increase of BaM content. Before magnetization, the relative permeability of the composite ferrites at 1 GHz ranged from 1.65 to 2.40, while it ranged from 1.61 to 2.30 after magnetization. After fitting the magnetic spectrum, it was observed that the equivalent applied field H increased after magnetization, and this increase was equivalent to the increase in anisotropic field of the samples. Moreover, H increased with the increase of BaM content, and the magnetic quality factor of the samples increased from 25–46 before magnetization to 34–102 after magnetization. The relative dielectric constants of the composite ferrites before and after magnetization ranged from 6.76 to 8.26 and 6.42 to 8.77, respectively, with no significant changes. The dielectric loss angle is slightly reduced to about 0.001. The characteristic impedance of Z/5%–40 % BaM ferrites is about 0.5, and the miniaturization factor ranges from 4.49 to 3.21. Additionally, these composites have low losses, making them suitable for UHF antenna miniaturization. [ABSTRACT FROM AUTHOR]

In this paper, Injection molding, debinding and sintering of ZrO 2 ceramic modified by silane coupling agent (A151) were studied by measuring the melt index of feedstocks, the soluble removal ratio of green parts, the bending strength of green and sintered parts, the surface and fractural morphologies of sintered parts. The results showed that the melt index of ZrO 2 feedstocks, the weight removal ratio of soluble binders, and the bending strength of green parts increased after adding A151. When the density of sintered parts was between 5.97–6.03 g/cm3, it was not the main factor influencing the bending strength. However, the bending strengths of sintered parts decreased due to microcrack formation when thermal debinding process was too fast or slow. The interesting phenomenon of the abnormal grain growth with transgranular fracture in the sintered parts obviously occurred above 1550 ℃, which made the effect of sintering temperature on the strength become complex. [ABSTRACT FROM AUTHOR]

The structural, heat capacity, and magnetic properties of Y2Mo2(1-x)Ti2xO7 were investigated in this work. Y2Mo2(1-x)Ti2xO7 maintains the pyrochlore structure, but lattice constants are observed to decrease continuously with the Ti4+ doping. The magnetic measurements indicate a magnetic phase transition at low temperature for all Ti-doped samples, and the Ti4+ doping suppresses the transition temperature. This is ascribed to the diluted effect of nonmagnetic Ti4+ substitution of magnetic Mo4+. The heat capacity data confirm that the low-temperature magnetic phase is spin glass in the Ti4+-doped Y2Mo2(1-x)Ti2xO7 system. The M(H) data reveals the coexistence of antiferromagnetic and ferromagnetic interactions at low temperatures. [ABSTRACT FROM AUTHOR]

The L -band and S-band electromagnetic waves are widely utilized in radar and satellite communications. This paper reports the successful synthesis of 85.8% content Ba 3 Co 2 Fe 24 O 41 (Co 2 Z) at a relatively low temperature of 1150 °C using the solid-phase method with BaFe 12 O 19 (BaM) and Ba 2 Co 2 Fe 12 O 22 (Co 2 Y) as precursors. The Co 2 Z samples were confirmed to have been successfully synthesized using X-ray diffraction (XRD) and thermogravimetry/differential scanning calorimetry (TG-DSC) spectra. Scanning electron microscopy (SEM) images revealed that the sintered samples exhibited large grains (>10 µm). Vibrating-sample magnetometry (VSM) data indicated that the synthesized Co 2 Z samples possessed distinct soft magnetic properties. X-ray photoelectron spectroscopy (XPS) results showed that the Fe3+ content decreased with the increase in synthesis temperature. The samples synthesized at 1110 °C − 1280 °C had a permeability of 10–20, a cut-off frequency of approximately 1 GHz, and a dielectric constant of 10–30. When the thickness of the sample synthesized at 1150 °C was 3.9 mm, the frequency range of the reflection loss (RL)< −10 dB was 2.55 GHz (0.98–3.53 GHz), with 1.77 GHz as the center frequency, and RLmin was − 57.8 dB. This observation indicates that the effective absorption bandwidth of the samples covers the entire L and S bands, which significantly satisfies practical applications within the military and civilian sectors. • Low temperature and wide temperature synthesis of Co 2 Z. • Achieving broadband absorption in the L -band (1–2 GHz) and S-band (2–4 GHz) solely through Co 2 Z ferrite absorbing materials. • The absorption of electromagnetic waves is mainly dominated by the magnetic loss of natural resonance. • provide the wave absorbing properties of Co 2 Z, which can be applied to other composite wave absorbing materials as a wave absorber. [ABSTRACT FROM AUTHOR]

In this work, the structural and magnetic properties in ZnCr2−xGaxO4 were investigated. In ZnCr2−xGaxO4, Ga3+ ions substitute partial Cr3+ ions and occupy the B sites. ZnCr2O4 undergoes a paramagnetic-antiferromagnetic transition at 12 K. In ZnCr2−xGaxO4, the antiferromagnetic short-range correlation occurs below 60 K above T N . The Ga3+ doping weakens the antiferromagnetic nearest-neighbor exchange interaction (J1) and induces ferromagnetic next-nearest-neighbor exchange interaction (J2) among the B site magnetic ions. The generation of the ferromagnetic J2 is ascribed to structure distortion induced by the Ga3+ doping. [ABSTRACT FROM AUTHOR]

• The state of art on low-frequency magnetic shielding of composites is presented. • Theoretical models of single-layer and multi-layer magnetic shielding are demonstrated. • The permeability calculation method based on hysteresis properties is summarized. • Stacked, coating and foam structures and the structural-material synergistic effect are described. • Challenges and prospects of composites applied in magnetic shielding are highlighted. The ultra-low magnetic field environment is essential for the research of fundamental physics and further application of biomedicine and space exploration etc. The single material structure is hard to meet the increasing demand for better shielding performances, whereas the composite shows great potential in addressing this problem. However, the state of art summary about magnetic shielding of composites, especially at low frequencies is insufficient. This review first introduces the magnetic shielding mechanism and the theoretical model of the shielding factor. The calculation method of permeability and the importance of accurate hysteresis properties characterization of magnetic composites are systematically discussed. Subsequently, the current status of magnetic shielding investigation on composite structures including stacked, coating, and foam forms is generalized. Emerging strategies for composite materials to further enhance shielding performances using the synergistic effect of structural and material properties are described. Finally, the challenges faced by composite materials in structural design and mechanism exploration of magnetic shielding are presented, providing a fresh perspective for its development. [ABSTRACT FROM AUTHOR]

• The new Mn ferrite with low power loss at high frequencies of 1–3 MHz over a wide temperature range of 25–140 °C was successfully developed. • Power loss was divided into hysteresis loss (P hv), eddy current loss (P ev) and residual loss (P rv), and the effect of Ta 2 O 5 on each part of power loss at high frequencies was investigated. • Small content of Ta 2 O 5 segregates at grain boundaries and reduces P hv , P ev and P rv. • The mechanism of reduction of P hv , P ev and P rv by the Ta 2 O 5 addition was clarified. Dramatic increase of power loss in the MHz frequency range is the bottleneck problem for MnZn ferrites to be applied in high-frequency power electronic devices. In this work, manganese ferrites with low power loss in the frequency range of 1–3 MHz have been developed by the addition of Ta 2 O 5. The manganese ferrite with 300 ppm Ta 2 O 5 exhibits excellent P cv performance. P cv at 25 °C is as low as 41, 94 and 164 kW/m3 under measurement conditions of 1 MHz/50 mT, 2 MHz/50 mT and 3 MHz/30 mT, respectively. Excellent temperature stability of power loss in the temperature range of 25–140 °C is also achieved in this sample. Power loss was divided to three parts of hysteresis loss, eddy current loss and residual loss. Ta 2 O 5 segregates at grain boundaries and reduces all three parts of loss. The mechanism of Ta 2 O 5 influence on each part of loss has been clarified. [ABSTRACT FROM AUTHOR]

• Mode I fatigue delamination tests are conducted and mode II R -curve behaviour of fatigue delamination has been observed. • A fatigue delamination model is proposed to characterize the combined effects of fiber bridging and stress ratio on the mode II fatigue delamination growth behaviour. • All fatigue data collapse into one single master curve in the log–log plot if using the proposed model. • The model has been further validated by extra public fatigue data of other material type and interfaces. Shear-dominated delamination is among one of the most common damages types. Deep understanding of the mode II fatigue delamination growth (FDG) behaviour is critically important for the damage tolerance design of composite laminates. Researchers have paid much attention to mode II FDG behaviour in unidirectional laminates and its stress ratio effect. However, the FDG behaviour in the widely used multidirectional laminates with effects of fiber bridging is still lack of studies. This work investigates FDG behaviour of multidirectional laminates under three kinds of stress ratio by using end-notch flexure set-up. Corrected beam theory with effective crack length is applied for calculating strain energy release rate (SERR), which can avoid visual observation for the delamination length. The R -curve behaviour of fatigue delamination has been observed. In addition, a FDG model has been proposed to characterize the combined effects of fiber bridging and stress ratio on the mode II FDG behaviour. It is found that all fatigue data collapse into one single master curve. The proposed model is also validated by data from public literature results. [ABSTRACT FROM AUTHOR]

• Co-Ba composite ferrites (CBCF) insulation layer was successfully cladded on the surface of Fe powder by a simple method. • Clausius-Maxwell formula model was used to simulate permeability in Fe@Co-Ba composite ferrites theoretically. • The SMCs coated with CBCF maintains high permeability (up to 121) and low core loss (129 kW/m3 at 20 mT, 100kHz). • Evolution of the Co-Ba composite ferrites coating with the annealing temperature is observed by BSEM images. To balance the core loss and permeability of soft magnetic composites (SMCs), a Co-Ba composite ferrite insulation layer was employed to clad the surface of reduced iron powder by sol-gel method. The successful preparation of the honeycomb-like Co-Ba composite ferrite coating layer was verified by scanning electron microscopy (SEM), the composition of the coating was determined by X-ray diffraction (XRD), and the magnetic properties were tested with a B-H curve analyzer. BSEM images of the polished cross-section and core loss separation results confirmed that an excessively high annealing temperature causes the composite ferrite insulation layer to fail. A high effective permeability of up to 121 at 300 kHz and low core loss (P cv) of 129 kW/m3 at 100 kHz and 0.02 T were obtained in prepared samples at the optimized annealing temperature of 500 °C. Subsequently, simulation analysis based on the Clausius-Maxwell formula model was used to confirm the feasibility of the enhancement on effective permeability in Fe@Co-Ba composite ferrite theoretically. The agreement between simulation and experimental results further indicated that a good balance between the core loss and permeability of Fe-based SMCs was achieved by Co-Ba composite ferrite cladding. [ABSTRACT FROM AUTHOR]

• The quick heating rate in thermal debinding resulted in the CuO precipitate. • The CuO precipitation was associated with the small amounts of remaining binders. • The quick heating rate in themal debinding resulted in the intergranular fracture. • The slow debinding (0.6 °C/min) improved bending strength and magnetic properties. NiCuZn ferrite ceramics were prepared by injection molding, debinding and sintering at 1150 °C. The effects of heating rate in thermal debinding on microstructure, bending strength and magnetic properties of sintered samples were investigated by scanning electron microscopy with energy-dispersive X-ray spectroscopy, X-ray diffraction, the Dual Column Tabletop Testing Machine, RF impedance Analyzer and B-H curve analyzer. The results showed the heating rate in thermal debinding played an important role on the sintered NiCuZn ferrite prepared by injection molding. When the heating rate in thermal debinding was quick above 1.2 °C/min in the lager cuboid samples, CuO precipitate was found at the grain boundary of ferrite and the intergranular fracture occurred, which was different from the normal transgranular fracture under the condition of slow heating rate. Furthermore, the density, bending strength, permeability and core loss of the sintered samples were improved with the decrease of heating rate. The influencing mechanism of thermal debinding on the difference was also discussed. [ABSTRACT FROM AUTHOR]

For composite multidirectional laminates widely used in engineering, there is still no effective model to characterize the fatigue delamination behavior with the combined effects of fiber bridging and stress ratio. A new fatigue delamination model was thus proposed in this study to deal with this problem. The model was established based on the fatigue driving force and fatigue delamination resistance, which characterized the effects of stress ratio and fiber bridging, respectively. A series of mode I fatigue delamination tests on composite multidirectional laminates were conducted under various stress ratios (0.1, 0.3 and 0.5) and different pre-crack lengths. Both the experimental results of this study and public fatigue data from laminates with other materials and various interfaces showed that a single master curve with a narrow band can be obtained by using the new model for all fatigue data under different stress ratios and fiber bridging effects. In addition, the determined model parameters obtained from fatigue data under specific stress ratios were used for predicting the fatigue delamination behavior under other stress ratios. Good agreements between the predictions and experimental results can be achieved, which further indicated the model's applicability. [ABSTRACT FROM AUTHOR]

The schematic of the preparation of the coated iron powder in the reactor by a one-pot synthesis method. The above schematic diagram can be clearly stated: The surface of iron powder is covered by a lot of hydroxyl groups. After placing the reactor under isothermal treatment, the aluminum ions begin to hydrolyze. The hydroxyl groups of hydrolysates form chemical bond with the hydroxyl groups of iron powder surface. Therefore, the precursor of alumina is formed on the surface of iron powder. Besides, the surfactant suppressed the formation of the alumina insulating coating to form a denser and smoother insulating coating on the surface of the iron powder. • Al 2 O 3 can be formed on the surface of iron powder by one-pot synthesis method. • The thickness of alumina insulating coating can be controlled by aluminum nitrate concentration. • The formation model of the alumina insulation layer was established. • Using the surfactant can help form the denser and smoother insulating coating. In this work, the effects of the Al 2 O 3 insulating coating and surfactant on magnetic properties of the iron powders coated with Al 2 O 3 by one-pot synthesis method were investigated. The morphology, phase composition and magnetoelectric properties of iron powders coated with Al 2 O 3 were tested respectively. Compared with uncoated iron powder, the composite powder of Al 2 O 3 insulating layer not only has better permeability stability in the frequency range of 5–300 kHz, but also has lower core loss, especially eddy current loss in the frequency range of 5–100 kHz. The surface of iron powder modified by surfactant will change crystallization process of aluminum hydroxide. After the addition of dodecyl trimethyl ammonium bromide (DTAB) as the surfactant, the Al 2 O 3 insulating coating becomes denser and smoother, and the core loss of coated powders is further reduced. [ABSTRACT FROM AUTHOR]

In this paper, Fe-based soft magnetic composites (SMCs) hydrothermally coated with lithium aluminum oxide (Li–Al–O) with better magnetic properties and lower core losses than Al 2 O 3 coated layers have be investigated. The microstructure and composition of the coating and magnetic properties of the composites were determined by scanning electron microscopy (SEM), X-ray diffraction (XRD) and B–H curve analyzer. Those results revealed that when Li 2 CO 3 was added to the aluminum nitrate solution, the originally formed Al 2 O 3 coating layer converted to a layer with a mixture of several lithium aluminum oxides. Fe-based SMCs coated with lithium aluminum oxide showed lower core losses, higher and stable effective permeability as compared with iron rings coated with Al 2 O 3 , especially in high frequency range of 100–300 kHz. The above schematic diagram can be clearly stated: In this work, iron powders, aluminum nitrate, lithium carbonate, and deionized water were simultaneously added to the poly tetra fluoroethylene liner. As the reaction proceeds, The Al3+ and Li+ which adsorbed on the surface of the iron powders combined with the OH− in water form the precursor of the Li–Al–O. The iron powders coated with the precursor were calcined at a high temperature to obtain the lithium aluminum oxide-coated iron powders. And then, the calcined iron powders were subjected to compression molding and annealing to obtain the Fe-based SMCs. Image 1 • Li-Al-O can be formed on the surface of iron powders by hydrothermal synthesis method. • The thickness of Li-Al-O insulation layer can be controlled by concentrations of Al(NO 3) 3 and Li 2 CO 3. • Comparing with Al 2 O 3 , the Fe-based SMCs coated with Li-Al-O coating have higher, more stable effective permeability and lower total core losses. [ABSTRACT FROM AUTHOR]

Calcium-overload-mediated tumor therapy has received considerable interest in oncology. However, its efficacy has been proven to be inadequate due to insufficient calcium ion concentration at the tumor site coupled with challenges in facilitating efficient calcium uptake by tumors, leading to unsatisfactory therapeutic outcomes. In the present study, calcium carbonate nanoshell mineralized ferric polydopamine nanoparticles (Fe-PDA@CaCO 3 NPs) were prepared for achieving Ca 2+ -overload-mediated tumor therapy. Upon entering the tumor site, the pH-responsive CaCO 3 layer, acting as a "Ca 2+ storage pool", rapidly degraded and released high quantities of free Ca 2+ within the weakly acidic environment. The Fe-PDA core, with its excellent photothermal conversion properties, could significantly increase the temperature upon exposure to near-infrared (NIR) light irradiation, thereby activating the TRPV1 channel and leading to a large influx of released Ca 2+ into the cytoplasm. Furthermore, the exposed Fe-PDA core could react with the tumor-overexpressed hydrogen peroxide (H 2 O 2 ) to efficiently produce hydroxyl radicals (•OH), significantly increasing intracellular reactive oxygen species (ROS) levels and thus inhibiting the activity of the Ca 2+ efflux pump, resulting in a high intracellular Ca 2+ concentration. Ultimately, the increase in calcium/ROS levels could disrupt mitochondrial homeostasis and activate the apoptosis pathway. The current work presents a promising approach for tumor therapy using photothermal-enhanced calcium-overload-mediated ion interference therapy and chemodynamic therapy.

Chemodynamic therapy (CDT) is a novel tumor treatment method by using hydroxyl radicals ( • OH) to kill cancer cells. However, its therapeutic effects are strictly confined by the short lifespan of • OH and reduced • OH generation speed. Herein, an effective CDT is achieved by both improving • OH lifetime and long-lasting generating • OH through intraparticle electron transfer within heterogeneous nanoparticles (NPs). These heterogeneous NPs are composed of evenly distributed Cu and Fe 3 O 4 (CFO NPs) with large interaction interfaces, and electrons tend to transfer from Cu to Fe 3 O 4 for the appearance of ≡Cu 2+ and increase in ≡Fe 2+ . The generated ≡Cu 2+ can interact with GSH, which prolongs the lifespan of • OH, produces ≡Cu + for higher speed • OH generation with H 2 O 2 , and induces cell ferroptosis for tumor therapy. The improved ≡Fe 2+ can also improve the • OH release under H 2 O 2 until Cu is depleted. As a result, a sustainable • OH generation is achieved to promote cell apoptosis for effective tumor therapy. Since H 2 O 2 and GSH are only overexpressed at tumor, and CFO NPs can degrade in the tumor microenvironment, these NPs are with high biosafety and can be metabolized by urine. This work provides a novel biomaterial for effective cancer CDT through intraparticle electron transfer., (© 2024 The Author(s). Advanced Science published by Wiley‐VCH GmbH.)

To maintain a comfortable indoor living environment in low latitude or tropical regions, humans consume significant amounts of electrical energy in air conditioning, leading to substantial CO 2 emissions. Passive daytime radiative cooling (PDRC) allows objects to cool down during the daytime without any energy consumption by dissipating heat through the atmospheric transparency window (8-13 µm) to outer space, which has garnered significant attention. However, the practical applications of common PDRC materials are hindered by their poor optical selectivity and high-reflective silver backing. Additionally, the availability of artificial photon emitters with complex structures and excellent performance is also limited by their high cost. Herein, a novel multilayer prismatic photonic metamaterial film without any silver reflector, easily scalable and produced by a roll-to-roll method is demonstrated, which exhibits ≈96.4% sunlight reflectance (0.3-2.5 µm) and ≈97.2% emissivity in mid-infrared (IR) (8-13 µm). At an average solar intensity of ≈920 W m -2 , it is on average 6.8 °C below ambient temperature during the day and theoretically yields a radiative cooling power of 88.9 W m -2 . Furthermore, the film exhibits excellent hydrophobicity, superior flexibility, and robust mechanical strength, providing an attractive and viable pathway for practical applications addressing the pressing challenges of climate and energy issues., (© 2023 Wiley‐VCH GmbH.)

Alternative splicing (AS) is a crucial mechanism in post-transcriptional regulation, contributing significantly to the diversity of the transcriptome and proteome. In this study, we performed a comprehensive AS profile in nine tissues obtained from Duroc (lean-type) and Luchuan (obese-type) pigs. Notably, 94,990 AS events from 14,393 genes were identified. Among these AS events, it was observed that 80% belonged to the skipped exon (SE) type. Functional enrichment analysis showed that genes with more than ten AS events were closely associated with tissue-specific functions. Additionally, the analysis of overlap between differentially alternative splicing genes (DSGs) and differentially expressed genes (DEGs) revealed the highest number of overlapped genes in the heart and skeletal muscle. The novelty of our study is that it identified and validated three genes ( PYGM , MAPK11 and CAMK2B ) in the glucagon signaling pathway, and their alternative splicing differences were highly significant across two pig breeds. In conclusion, our study offers novel insights into the molecular regulation of diverse tissue physiologies and the phenotypic differences between obese- and lean-type pigs, which are helpful for pig breeding.

The combination of chemo/chemodynamic therapy is a promising strategy for improving antitumor efficacy. Herein, metal-phenolic network nanoparticles (NPs) self-assembled from copper ions and gallic acid (Cu-GA) are developed to evoke apoptosis and cuproptosis for synergistic chemo/chemodynamic therapy. The Cu-GA NPs are biodegraded in response to the highly expressed glutathione (GSH) in tumor cells, resulting in the simultaneous release of Cu + and GA. The intracellular GSH content is dramatically reduced by the released GA, rendering the tumor cells incapable of scavenging reactive oxygen species (ROS) and more susceptible to cuproptosis. Meanwhile, ROS levels within the tumor cells are significantly increased by the Fenton-like reaction of released Cu + , which disrupts redox homeostasis and achieves apoptosis-related chemodynamic therapy. Moreover, massive accumulation of Cu + in the tumor cells further induces aggregation of lipoylated dihydrolipoamide S-acetyltransferase and downregulation of iron-sulfur cluster protein, activating cuproptosis to enhance the antitumor efficacy of Cu-GA NPs. The experiments in vivo further demonstrate that Cu-GA NPs exhibited the excellent biosafety and superior antitumor capacity, which can efficiently inhibit the growth of tumors due to the activation by the tumor specific GSH and hydrogen peroxide. These Cu-based metal-phenolic network NPs provide a potential strategy to build up efficient and safe cancer therapy., (© 2023 Wiley-VCH GmbH.)

The encapsulation of fullerenes by carbon nanorings has gained increasing attention because of the unique molecular structure and special properties of the formed complexes. The host-guest interactions between the fullerenes and the carbon nanorings can influence the metal ion orientation and the molecular electronic structure. In this study, we hooped a series of carbide cluster metallofullerenes, namely Sc 2 C 2 @C 2v (5)-C 80 , Sc 2 C 2 @C 3v (8)-C 82 , and Sc 2 C 2 @D 2d (23)-C 84 , with molecular carbon nanorings of [12]cycloparaphenylene ([12]CPP) and perfluoro[12]cycloparaphenylene (PF[12]CPP). The formed complexes were computationally studied via dispersion-corrected density functional theory calculations. The results showed that the deformation rate of PF[12]CPP after the formation of the fullerene-containing complexes was significantly smaller than that of [12]CPP. The binding energy and thermodynamic information showed that PF[12]CPP was more suitable for fullerene encapsulation. Moreover, charge population analysis showed that PF[12]CPP transferred more electrons to Sc 2 C 2 @C 2 n ( n = 40, 41, and 42) compared with [12]CPP. Energy decomposition and real-space function analyses of host-guest interactions revealed the characteristics and nature of the noncovalent interactions in the supramolecules. These results provide theoretical support for the study of host-guest systems based on metallofullerenes., Competing Interests: The authors declare no competing financial interest., (This journal is © The Royal Society of Chemistry.)

Chemodynamic therapy (CDT) is a booming technology that utilizes Fenton reagents to kill tumor cells by transforming intracellular H 2 O 2 into reactive oxygen species (ROS), but insufficient endogenous H 2 O 2 makes it difficult to attain satisfactory antitumor results. In this article, a H 2 O 2 -free CDT technique with tumor-specificity is developed by using pH-sensitive magnetic iron carbide nanoparticles (PEG/Fe 2 C@Fe 3 O 4 NPs) to trigger artemisinin (ART) to in situ form ROS. ART-loaded PEG/Fe 2 C@Fe 3 O 4 NPs are fabricated for the enormous release of Fe 2+ ions induced by the acidic conditions of the tumor microenvironment after magnetic-assisted tumor enrichment, which results in the rapid degradation of the PEG/Fe 2 C@Fe 3 O 4 NPs and release of ART once endocytosed into tumor cells. In situ catalysis reaction between the co-released Fe 2+ ions and ART generates toxic ROS and then induces apoptosis of tumor cells. Both in vitro and in vivo experiments demonstrate that the efficient Fe-enhanced and tumor-specific CDT efficacy for effective tumor inhibition based on ROS generation. This work provides a new direction to improve CDT efficacy based on H 2 O 2 -independent ROS generation., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Reactive oxygen species (ROS) are crucial molecules in cancer therapy. Unfortunately, the therapeutic efficiency of ROS is unsatisfactory in clinic, primarily due to their rigorous production conditions. By taking advantage of the intrinsic acidity and overproduction of H 2 O 2 in the tumor environment, we have reported an ROS nanoreactor based on core-shell-structured iron carbide (Fe 5 C 2 @Fe 3 O 4 ) nanoparticles (NPs) through the catalysis of the Fenton reaction. These NPs are able to release ferrous ions in acidic environments to disproportionate H 2 O 2 into • OH radicals, which effectively inhibits the proliferation of tumor cells both in vitro and in vivo . The high magnetization of Fe 5 C 2 @Fe 3 O 4 NPs is favorable for both magnetic targeting and T 2 -weighted magnetic resonance imaging (MRI). Ionization of these NPs simultaneously decreases the T 2 signal and enhances the T 1 signal in MRI, and this T 2 / T 1 switching process provides the visualization of ferrous ions release and ROS generation for the supervision of tumor curing. These Fe 5 C 2 @Fe 3 O 4 NPs show great potential in endogenous environment-excited cancer therapy with high efficiency and tumor specificity and can be guided further by MRI.