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Medical image segmentation is a crucial step in diagnosis and analysis of diseases for clinical applications. Deep convolutional neural network methods such as DeepLabv3+ have successfully been applied for medical image segmentation, but multi-level features are seldom integrated seamlessly into different attention mechanisms, and few studies have fully explored the interactions between medical image segmentation and classification tasks. Herein, we propose a feature-compression-pyramid network (FCP-Net) guided by game-theoretic interactions with a hybrid loss function (HLF) for the medical image segmentation. The proposed approach consists of segmentation branch, classification branch and interaction branch. In the encoding stage, a new strategy is developed for the segmentation branch by applying three modules, e.g., embedded feature ensemble, dilated spatial mapping and channel attention (DSMCA), and branch layer fusion. These modules allow effective extraction of spatial information, efficient identification of spatial correlation among various features, and fully integration of multi-receptive field features from different branches. In the decoding stage, a DSMCA module and a multi-scale feature fusion module are used to establish multiple skip connections for enhancing fusion features. Classification and interaction branches are introduced to explore the potential benefits of the classification information task to the segmentation task. We further explore the interactions of segmentation and classification branches from a game theoretic view, and design an HLF. Based on this HLF, the segmentation, classification and interaction branches can collaboratively learn and teach each other throughout the training process, thus applying the conjoint information between the segmentation and classification tasks and improving the generalization performance. The proposed model has been evaluated using several datasets, including ISIC2017, ISIC2018, REFUGE, Kvasir-SEG, BUSI, and PH2, and the results prove its competitiveness compared with other state-of-the-art techniques.

Background: At this stage, Chinese research on physical activity literacy is still in its infancy, and the domestic primary school students' physical activity literacy assessment questionnaire is also in a state of development. In this study, a set of questionnaire scales for measuring the physical activity literacy of primary school students was compiled according to the characteristics of primary school students in different school stages, and the population measurement was carried out by using this scale, and then the accuracy of the scale and the fit according to the Rasch model were judged. Methods: We compiled a set of scales for measuring the physical activity literacy of primary school students, and directly distributed the questionnaires to primary school students in four regions of Hebei Province, Sichuan Province, Shenzhen City and Qinghai Province for actual measurement. We also used Rasch analysis to study the single-dimensionality, reliability, resolution and fitting degree of the questionnaire to judge the accuracy of the scale, aiming to provide a strong reference for the subsequent revision and wide application of the questionnaire. Results: The item reliability coefficient of all questionnaires was 1, and the item separation degree was 16.08, 16.71 and 18.18, respectively, all of which were greater than 3, indicating that the internal consistency of the questionnaire was better and the students with different ability levels could be better distinguished. The one-dimensional hypothesis of the three questionnaires holds. The project-person figure shows that the difficulty of the questionnaire items can be well matched with the subject's ability level. The average values of Infit MNSQ and Outfit MNSQ in the questionnaire were between 0.5-1.5, and the overall fit was good, and the data were in good agreement with the ideal model. In the fitting statistics of a single entry, it was found that the three grade levels generally showed poor fitting on the questions of whether they should continue to exercise after injury, whether it was appropriate to be sedentary and inactive, whether weather with severe air pollution was suitable for outdoor sports, and motivation for sports tests and motivation to like challenges. In subsequent modifications, we will delete and improve these questions or modify the statements of these questions to appropriately increase the difficulty of the questions. Conclusion: The one-dimensional test passed, reliable and internally consistent of the questionnaire was high, the difficulty of the item and the matching degree of population ability were high, and the questionnaire fit the model well. The questionnaire as a whole can form a questionnaire on sports health literacy of primary school students with good reliability and validity.

BACKGROUND AND AIMS: Whether preoperative serum carbohydrate antigen (CA) 72-4 is an independent predictor of outcome and whether has an interaction between CA72-4 and the impact of carcinoembryonic antigen (CEA) on colorectal cancer (CRC) patients' risk of recurrence is still unknown. PATIENTS AND METHODS: Patients with pathologically confirmed stage I-III colorectal adenocarcinoma who received direct radical resection at 2 hospitals from 2008 to 2017 were collected. According to the levels of CEA and CA72-4 before operation, the patients were divided into 4 groups: Group A with normal CEA and CA72-4 levels preoperatively (CEA≤5.0 ng/mL,CA72-4≤6.9 U/mL, n=952) ;Group B had normal preoperative CEA but high CA72-4 levels (CEA≤5.0 ng/mL,CA72-4>6.9 U/mL, n=217) ；Group C had elevated preoperative CEA but normal CA72-4 (CEA>5.0 ng/mL,≤6.9 U/mL, n=574) ；Group D had both elevated preoperative CEA and CA72-4 (CEA>5.0 ng/mL, CA72-4>6.9 U/mL, n=182). The Kaplan-Meier survival curve and a COX regression model was used to estimate the correlation between preoperative CA72-4 and overall survival (OS) and recurrence-free survival (RFS). Results: A total of 3,651 patients (52.7%) are included in this study. Median age (IQR) : 60.0 (50.0, 68.0) years; Mean body mass index (BMI) (SD) : 22.718(3.256) kg/m2. Compared with normal CA 72-4 (≤6.9 U/mL, n=3252), patients with increased CA 72-4 (>6.9U/mL, n=399) had higher OS(HR:1.4;95% CI, 1.07-1.83; P = 0.0072). In Cox multivariate analysis, increased preoperative CEA and CA72-4 were associated with shorter RFS(HR:1.69;95% CI, 1.23- 2.32; P = 0.001) and OS (HR, 2.92;95% CI, 2.14-3.98; P < 0.001). However, patients with normal preoperative CEA, no matter if CA72-4 is increased or normal, were not associated with RFS and OS shortening, while patients with high CEA but normal CA72-4 were only associated with OS(HR:1.82;95% CI, 1.42-2.33; P Conclusion:CA72-4 is an independent predictor of outcome for patients with elevated preoperative CEA. The influence of preoperative CA72-4 level on prognosis is different under different CEA stratification. It is necessary to combine CA72-4 with CEA to predict the prognosis of patients.

We investigated the copy number variation (CNV) of PDGFRA pathway across all common cancer types as well as its clinical relevance. This study included a total of 10,678 patients with pan-cancerous species involving 33 types of cancers and patient information was obtained from The Cancer Genome Atlas. According to the PDGFRA pathway CNV, all samples were divided into copy number gain (CN gain) group and No CN gain group. The analysis of loss of heterozygosity (LOH) fraction, CNV burden, tumor mutation burden (TMB), and the number of immunogenic mutations were performed, as well as the correlation analysis of PDGFRA pathway CN gain with tumor-related signaling pathways and tumor-infiltrating immune cell subpopulations. The results showed that CN gain of PDGFRA pathway in the cancer patients was associated with significantly shorter overall survival. The CN gain of PDGFRA pathway was identified as a prognostic risk factor for some tumors. CN gain was accompanied by an altered percentage of LOH, CNV burden, TMB, the number of immunogenic mutations were increased and tumor-infiltrating immune cell subpopulations were less. While certain tumor-related signaling pathways, such as hypoxia, cell cycle, DNA repair, and epithelial-mesenchymal transition were more enriched in the CN gain group, quiescence, and inflammation pathways were more enriched in the No CN gain group. In conclusion, PDGFRA pathway CNV gain may be a poor prognostic factor in cancer patients.

BACKGROUND AND AIMS: Whether preoperative serum carbohydrate antigen (CA) 72-4 is an independent predictor of outcome and whether has an interaction between CA72-4 and the impact of carcinoembryonic antigen (CEA) on colorectal cancer (CRC) patients' risk of recurrence is still unknown. PATIENTS AND METHODS: Patients with pathologically confirmed stage I-III colorectal adenocarcinoma who received direct radical resection at 2 hospitals from 2008 to 2017 were collected. According to the levels of CEA and CA72-4 before operation, the patients were divided into 4 groups: Group A with normal CEA and CA72-4 levels preoperatively (CEA≤5.0 ng/mL,CA72-4≤6.9 U/mL, n=952) ;Group B had normal preoperative CEA but high CA72-4 levels (CEA≤5.0 ng/mL,CA72-4>6.9 U/mL, n=217) ；Group C had elevated preoperative CEA but normal CA72-4 (CEA>5.0 ng/mL,≤6.9 U/mL, n=574) ；Group D had both elevated preoperative CEA and CA72-4 (CEA>5.0 ng/mL, CA72-4>6.9 U/mL, n=182). The Kaplan-Meier survival curve and a COX regression model was used to estimate the correlation between preoperative CA72-4 and overall survival (OS) and recurrence-free survival (RFS). Results: A total of 3,651 patients (52.7%) are included in this study. Median age (IQR) : 60.0 (50.0, 68.0) years; Mean body mass index (BMI) (SD) : 22.718(3.256) kg/m2. Compared with normal CA 72-4 (≤6.9 U/mL, n=3252), patients with increased CA 72-4 (>6.9U/mL, n=399) had higher OS(HR:1.4;95% CI, 1.07-1.83; P = 0.0072). In Cox multivariate analysis, increased preoperative CEA and CA72-4 were associated with shorter RFS(HR:1.69;95% CI, 1.23- 2.32; P = 0.001) and OS (HR, 2.92;95% CI, 2.14-3.98; P< 0.001). However, patients with normal preoperative CEA, no matter if CA72-4 is increased or normal, were not associated with RFS and OS shortening, while patients with high CEA but normal CA72-4 were only associated with OS(HR:1.82;95% CI, 1.42-2.33; P Conclusion: CA72-4 is an independent predictor of outcome for patients with elevated preoperative CEA. The influence of preoperative CA72-4 level on prognosis is different under different CEA stratification. It is necessary to combine CA72-4 with CEA to predict the prognosis of patients.

It had been researched the thermal conductivity and dielectric properties of high thermal conductive (HTC) main insulation for the large and medium generator stator bars. The thermal conductivity was analyzed by orthogonal test for the adhesive composed of BN powders and Tung-maleic-anhydride epoxy resin, and the BN with different particle sizes were used in the adhesive. It analyzed the variation of thermal conductivity for the adhesive composite with different BN powder contents, and the best thermal conductivity in the adhesives was 2.27 W/(m K). The variation of the dielectric properties was analyzed for the HTC adhesive by frequency-domain spectrum. It was detected by scanning electron microscope for the dispersion of the BN particles in TAEP and the bond state between the BN particles. The results indicated that the thermal conductivity of the best adhesives was increased by 13 times, and the other properties were almost the same as that of TAEP. Therefore, the HTC adhesive could be used in the main insulation of the large generator stator bars.

Medical image segmentation is a crucial step in the clinical applications for diagnosis and analysis of some diseases. U-Net-based convolution neural networks have achieved impressive performance in medical image segmentation tasks. However, the multi-level contextual information integration capability and the feature extraction ability are often insufficient. In this paper, we present a novel multi-level context fusion network (MCF-Net) to improve the performance of U-Net on various segmentation tasks by designing three modules, hybrid attention-based residual atrous convolution (HARA) module, multi-scale feature memory (MSFM) module, and multi-receptive field fusion (MRFF) module, to fuse multi-scale contextual information. HARA module was proposed to effectively extract multi-receptive field features by combing atrous spatial pyramid pooling and attention mechanism. We further design the MSFM and MRFF modules to fuse features of different levels and effectively extract contextual information. The proposed MCF-Net was evaluated on the ISIC 2018, DRIVE, BUSI, and Kvasir-SEG datasets, which have challenging images of many sizes and widely varying anatomy. The experimental results show that MCF-Net is very competitive with other U-Net models, and it offers tremendous potential as a general-purpose deep learning model for 2D medical image segmentation.

Purpose: This study aimed to investigate postoperative CEA combined with tumor deposition for risk stratification of postoperative recurrence of stage II-III colon cancer.Methods: A retrospective analysis of 761 patients who underwent radical surgery for stage II-III colon cancer from April 2008 to January 2019. Patients were grouped into 3 cohorts: normal postoperative CEA without tumor deposits（TD）, normal postoperative CEA with TD, and elevated postoperative CEA. Cox proportional hazards regression model was used to analyze the independent recurrence prognostic factors of patients with recurrence-free survival (RFS). The Kaplan-Meier method was used to draw the patient's RFS curve.Results: The median follow-up period of all patients was 49.73 months. A total of 761 patients (452 [59.4%] male; median [IQR] age, 69 [50-67] years) were identified. The 3-year RFS of 60 patients with normal postoperative CEA and positive TD was 51.1% (95% CI, 39.8%-65.5%), and the 3-year RFS of 103 patients with elevated postoperative CEA was 47.7% (95% CI, 38.5%-58.3%). (Patients with normal postoperative CEA and positive TD vs Patients with elevated postoperative CEA: HR, 1.04; 95% CI, 0.67-1.60; P = 0.877). Multivariate analysis of the COX proportional hazards model showed that normal postoperative CEA with TD (HR, 2.0; 95% CI, 1.1-3.5) is independently associated with shorter RFS.Conclusion: Patients with normal postoperative CEA still have a higher risk of recurrence if combined with tumor deposits. It is necessary to incorporate postoperative CEA and tumor deposition into high-risk factors for postoperative recurrence of colon cancer for management.

Rapid detection of long-chain alcohol vapors with high energy is highly desirable owing to their inflammable and explosive properties. However, chemoresistive sensors based on metal oxides have bee...

Melanin and its analogue polydopamine (PDA) have attracted considerable attention in biomedical science due to their surface-rich metal binding sites, excellent adhesion and good biocompatibility. Bacterial infections at the wound site and uncontrolled bleeding are associated with a high risk of death, and the prevention of wound infections remains a major challenge. On this basis, the four nanoparticles (NPs) of melanin, PDA, copper ion-loaded melanin (Cu(ii) loaded melanin) and copper ion-loaded PDA (Cu(ii) loaded PDA) were studied in terms of antibacterial and wound healing capabilities. The in vitro experiments showed that Cu(ii) loaded PDA NPs had good blood compatibility and low cytotoxicity, showing the best antibacterial effect in comparison with other samples. Not only could the slow release of copper ions from the nanoparticles kill bacteria, but also the phenolic hydroxyl group and amine groups of PDA NPs played a synergistic role in bacterial death. In wound healing experiments, the Cu(ii) loaded PDA NPs could easily and tightly bind with biological tissue, demonstrating excellent hemostasis, antibacterial and wound healing capabilities. In summary, the excellent properties of Cu(ii) loaded PDA NPs made them a safe and effective drug for preventing wound infection and promoting healing.

Two kinds of 1D core–shell nanorods silver@polydopamine (Ag@PDA) and silver@zinc oxide (Ag@ZnO) were successfully synthesized and doped into polyvinylidene fluoride (PVDF) to fabricate composites. The different surface modification effects between the organic PDA shell and inorganic ZnO shell on structure and dielectric properties of PVDF composites were investigated. Results indicated that the ZnO shell showed a crystalline structure, while the PDA shell is amorphous. Due to the difference in crystal structure of the coating shell, the Ag@ZnO/PVDF composites showed a better dielectric performance than the Ag@PDA/PVDF composites, while the Ag@PDA/PVDF showed excellent mechanical properties. The crystallized structure of ZnO not only promoted the crystal conversion of PVDF molecules, but also effectively limited the movement of charge carriers in composites. In the case of 10wt% fillers' content and before breakdown strength, the energy storage densities of Ag@PDA/PVDF and Ag@ZnO/PVDF composites are 79.53% and 209.2% higher than that of pure PVDF films, respectively. Moreover, the charge/discharge efficiency of Ag@ZnO/PVDF composite is also higher than that of pure PVDF and Ag@PDA/PVDF composite. When testing at 1800 kV/cm electrical strength, the energy storage density of Ag@ZnO/PVDF composite increases to 4.02 J/cm3.

It is an effective way to improve the toughness, dielectrical property, and electrical property of epoxy vinyl ester resin (VE) via embedding hyperbranched polymer. In the present study, a new kind of flexible chain blocking hyperbranched polyester (HBP) with the rich unsaturated double bond has been designed and synthesized. The hyperbranched structure of HBP was characterized by NMR and FT-IR. Based on dielectric property test, it could be found that HBP could reduce dielectric constant (e) of VE compound, and the interaction between the polar functional groups in the flexible chain and epoxy resin could reduce dielectric loss (tgδ) within a certain frequency. The results of mechanical measurement showed that the addition of HBP could improve the mechanical properties of the resin systems. When HBP content was 20 wt%, the impact strength of modified epoxy anhydride curing compound reached 18.9 kJ/mm−2, and the bending strength of modified epoxy anhydride curing compound reached 134.0 MPa.

A new type of core–shell graphene@poly(dopamine)-Ag nanoplatelets was developed to improve the dielectric properties of thermoplastic polyurethane (TPU) nanocomposites. Dopamine was oxidatively polymerized to form a polydopamine (PDA) layer on the surface of graphene nanosheets (Gns), and then Ag nanoparticles were chemically reduced by silver nitrate and uniformly embedded on the surface of PDA. This obtained Gns@PDA-Ag core–shell nanoplatelets were filled into TPU to prepare a flexible dielectric material. The microstructure and dielectric performances were tested. Results indicated that the Gns@PDA-Ag core–shell nanoplatelets were evenly dispersed in TPU matrix. Moreover, the addition of Gns@PDA-Ag core–shell nanoplatelets could effectively improve the dielectric constant of the composite. Under low-frequency test conditions, the dielectric constant of the TPU/Gns@PDA-Ag (4 wt%) nanocomposite was 117.81, which was about 14 times higher than that of pure TPU. Theoretical analysis shows that the PDA shell not only promoted the uniform dispersion of Gns in TPU matrix, but also enhanced the interface bonding between the nanoplatelets and the TPU matrix. Moreover, introducing ultra-small Ag nanoparticles had effectively decreased the dielectric loss and conductivity of TPU/Gns@PDA-Ag composites due to its coulomb blockade and quantum trapped carrier structure effects, which resulted in the improvement of energy storage characteristics of composite.

There are higher requirements for various properties of copper-clad laminates under high-frequency conditions with the rapid development of information transmission. In the present study, a new kind of laminate is prepared by adding hyperbranched polyester (HBP) which is co-blocked by Caprylic acid and Hexanoic acid, applying to the high-frequency CCL. The hyperbranched structure of HBP was characterized by NMR and FT-IR. Based on dielectric property test, it could be found that HBP could reduce the dielectric constant (e) and the dielectric loss (tgδ) of laminate, the dielectric constant of laminate was 4.29 and the dielectric loss was 0.0037 at the frequency of 107 Hz. The method to lower the e is via increasing the content of free volume or reducing the content of polarizable functional groups in the system. Also the insulation test and the mechanical test showed the great properties of the laminate and the results of the flame retardant, moisture absorption and peel strength meet the application requirements of high-frequency CCL.

Polypropylene (PP) is considered to be a potential eco-friendly cable insulation material. However, space charge accumulation in PP under high electric stress limits its application for HVDC cable. In this paper, PP was modified with 4-acetoxystyrene (AOS) by melt grafting to improve electric properties. The molecular structure of the polypropylene-graft-4-acetoxystyrene (PP-g-AOS) was characterized by means of Fourier Transform Infrared Spectroscopy (FT-IR). The effects of temperature, screw speed, time, initiator content and monomer content on grafting degree of PP-g-AOS were investigated. Furthermore, the influence of grafting degree of PP-g-AOS on space charge suppression, volume resistivity and dc breakdown field strength was investigated. The FT-IR result showed that AOS was successfully grafted onto PP. It was found that under the proper grafting conditions, the obtained PP-g-AOS exhibited a maximum grafting degree of 1.31%. Moreover, PP-g-AOS with grafting degree of 1.14% can suppress space charge efficiently, and increase both volume resistivity and dc breakdown strength. This provides a new idea for the study of polypropylene HVDC cable insulation.

A series of polyimide/AlN composite films and polyimide/AlN/BN composite films with different contents were prepared by using polyimide as organic matrix, AlN and BN as inorganic fillers. The filli...

ImportanceFibromyalgia (FM) is a common clinical chronic disease, mainly manifested as generalized chronic muscle pain and discomfort throughout the body, often accompanied by various emotional disorders such as depression, anxiety, cognitive impairment and sleep disorder, which seriously affects the quality of life of patients. However, there has not been adequately good treatment methods in clinically, so it is urgent to seek a better treatment method. In this study, duloxetine combined with ozone pain point injection was used to treat FM patients, and the clinical efficacy of the patients was observed.ObjectiveTo determine whether duloxetine combined with ozone pain point injection is safe and efficacious in the treatment of Fibromyalgia.MethodsAccording to the final treatment plan selection, the patients diagnosed with FM in the Pain Department of Shiyan Taihe Hospital, were selected from July 2017 to July 2020. After communication and written consent, 66 patients were injected with drugs and ozone pain point. Actually 60 cases finished the study procedure and follow-up. The age ranged from 22 to 57 years, and the course of the disease ranged from 2 to 8 years. In this study, a crossover design was adopted, and random number table method was used to enter the group. The patients were randomly divided into duloxetine group (group D), ozone injection group (group O) and duloxetine-ozone injection group (group D+O), with 20 patients in each group. Each group was given corresponding treatment. VAS, FIQ, PSQI and HAMD scales were used to evaluate and calculate the number of pain points, so as to observe and evaluate the clinical efficacy of patients.ResultsIn terms of pain, there was no significant difference among the groups before treatment. After 2 weeks and 4 weeks of treatment, the VAS scores in each group were significantly lower than before intervention (F=324.365 P < 0.05). The number of pain points in each group was significantly lower than before intervention, and the difference was statistically significant (F=514.046 P < 0.05). It was observed that the analgesic effect of duloxetine combined with ozone pain point injection in the treatment of fibromyalgia was better than that of single therapy. There was no significant difference in quality of life among the groups before treatment. After 2 weeks and 4 weeks of treatment, the FIQ of each group was significantly lower than that before intervention, and the difference was statistically significant (F = 324.365, PConclusionThis study confirmed that duloxetine combined with ozone pain-point injection can effectively relieve pain in patients with FM, significantly improve the accompanying symptoms of sleep disorder and depression, and improve the quality of life of patients, which is worthy of clinical promotion.

Standing surface acoustic waves (SSAWs) have been extensively used as acoustic tweezers to manipulate, transport, and separate microparticles and biological cells in a microscale fluidic environment, with great potentials for biomedical sensing, genetic analysis, and therapeutics applications. Currently, there lacks an accurate, reliable, and efficient three-dimensional (3D) modeling platform to simulate behaviors of micron-size particles/cells in acoustofluidics, which is crucial to provide the guidance for the experimental studies. The major challenge for achieving this is the computational complexity of 3D modeling. Herein, a simplified but effective 3D SSAW microfluidic model was developed to investigate the separation and manipulation of particles. This model incorporates propagation attenuation of the surface waves to increase the modeling accuracy, while simplifies the modeling of piezoelectric substrates and the wall of microchannel by determining the effective propagation region of the substrate. We have simulated the SSAWs microfluidics device, and systematically analyzed effects of voltage, tilt angle, and flow rate on the separation of the particles under the SSAWs. The obtained simulation results are compared with those obtained from the experimental studies, showing good agreements. This simplified modeling platform could become a convenient tool for acoustofluidic research.

Thermal shock water quenching tests on porous ZrB2–SiC (ZS) ceramics with 8.7, 17.9 and 27.3% porosity were conducted after these specimens were oxidised in static air at a constant tempera...

Ferroptosis, a promising mechanism of killing cancer cells, has become a research hotspot in cancer therapy. Besides, advantages of polymeric nanomaterials in improving anticancer efficacy and reducing side effect are widely accepted. In this work, based on the property of polypodamine to chelate metal ions, ultrasmall poly(ethylene glycol)-modified polydopamine nanoparticles, (UPDA-PEG)@Fe2+/3+ nanoparticles, a novel ferroptosis agent, was rationally designed by chelating iron ions on ultrasmall polydopamine nanoparticles modified by PEG. This treatment led to a bigger specific surface area, which could support more reactive sites to chelate large number of iron ions, which is beneficial for exploring the detailed mechanism of ferroptosis-induced tumor cell death by iron ions. Also, the pH-dependent release of iron ions can reach approximately 70% at pH 5.0, providing the advantage of application in tumor microenvironment. The in vitro tests showed that the as-prepared NPs exhibit an effective anticancer effect on tumor cells including 4T1 and U87MG cells, yet ferric ions show a stronger ability of killing cancer cells than ferrous ions. Differences between ferrous ions and ferric ions in the ferroptosis pathway were monitored by the change of marker, including reactive oxygen species (ROS), glutathione peroxidase 4, and lipid peroxide (LPO), as well as the promoter and inhibitor of ferroptosis pathway. UPDA-PEG@Fe2+ nanoparticles induce ferroptosis that depends more on ROS; however, a more LPO-dependent ferroptosis is induced by UPDA-PEG@Fe3+ nanoparticles. Additionally, the in vivo studies using tumor-bearing Balb/c mice demonstrated that the as-prepared NPs could significantly inhibit tumor progression. UPDA-PEG@Fe2+/3+ nanoparticles reported herein represent the nanoparticles related to iron ions for chemotherapy against cancer through the ferroptosis pathway.

PurposeThe dispersity of graphene oxide (GO) has an important effect on the properties of epoxy resin (EP) composites. Many modification and dispersion methods require the use of inert solvents which do not participate in the modification reaction, although GO can be uniformly dispersed in water and alcohol solvents. Based on this requirement, several inert solvents were selected as dispersion solvents to find out the suitable inert solvent for GO dispersion into EP matrix.Design/methodology/approachSeveral inert solvents with different solubility parameters were selected as dispersion solvents to prepare GO/EP composite. The microstructure, mechanical properties, insulation properties, dielectric properties and thermal property of the composite were characterized, which was due to find suitable inert solvent for GO dispersion into EP matrix.FindingsThe dispersity of N, N-dimethylformamide (DMF) was the best stable suspension state when it was used as solvent instead of occurring sedimentation and agglomeration. Moreover, DMF was further confirmed as a suitable inert solvent for the dispersion of GO into EP according to the mechanical properties, insulation properties and thermal conductivity characterization.Research limitations/implicationsThe dispersion of GO in solvents has already been researched, but the traditional solvents, such as alcohols and water, has shown their limitations with the increase of modification methods, which were not suitable for the modification environment such as cyanate graft modification. Therefore, it was very important to choose a kind of inert solvent for dissolving EP matrix and dispersing GO better.Originality/valueSeveral inert solvents were used to disperse GO into EP, and the influence of different dispersing solvents on the adhesive was discussed through the analysis of the mechanical properties, insulation properties and thermal conductivity, which was due to explore the inert solvent suitable for GO dispersion.

A new kind of hyperbranched polymers was designed and prepared with flexible chain blocking in this paper. Not only the flexible chain blocking hyperbranched polyester could be used for a toughening agent about epoxy resin and the impact strength reached 29.8 kJ/mm2, but also reduces greatly the dielectric constant and the dielectric loss of the epoxy resin, and the lowest dielectric constant was 2.73 (107 Hz), as well the lowest dielectric loss was 0.002 (107 Hz), compared with the epoxy resin system modified with the traditional hyperbranched polyester. The results indicated that the flexible chain blocking hyperbranched polyester had offered free volume structure and flexible chain with epoxy resins chain formed the interpenetrating polymer networks which made transformation accomplish. The resins which had better toughness, low Dk, low dielectric loss and excellent insulation performance could be applied in various research and development fields, such as high frequency and low dielectric copper clad laminate and translucent structural adhesives, etc.

As advanced dielectric materials for the applications in electronics and electrical power systems with the ever-increasing requirements, the polymer-based dielectric nano-composites are brilliantly emerging. However, there are long standing challenges of the unsatisfactory electric breakdown strength and the heat accumulation induced by dielectric loss of composite. In this study, we propose an artificial nano-composite with excellent comprehensive performance by controlling the orientation of one-dimensional (1D) 0.5Ba(Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3 nanofibers (BZCT NFs) and adjusting the interaction between BZCT NFs and poly(vinylidene fluoride) (PVDF) matrix via SiO2 buffer layer. Remarkably, PVDF nano-composite with only 3 vol% aligned BZCT NFs coated by SiO2 (BZCT@SiO2 NFs, 3 vol% Aligned BZCT@SiO2-PVDF) possesses an impressive energy storage performance, including the superior Weibull characteristic breakdown strength (Eb) of ~576 kV/mm and the ultrahigh discharged energy density (Ue) of ~18.9 J/cm3. Meanwhile, the temperature distribution in this typical composite is more homogeneous according to the test and simulation results. This demonstrated work not only opens a new door to preparing an excellent performance of polymer-based dielectric nano-composites, but also points out a route to the industrialization of energy storage dielectrics.

Ferroptosis, a promising mechanism of killing cancer cells, has become a research hotspot in cancer therapy. Besides, advantages of polymeric nanomaterials in improving anticancer efficacy and reducing side effect are widely accepted. In this work, based on the property of polypodamine to chelate metal ions, ultrasmall poly(ethylene glycol)-modified polydopamine nanoparticles, (UPDA-PEG)@Fe

Two series of fluorinated copolymerized polyimide films with different dianhydride ratios were prepared via the conventional two-step method by using 4,4-oxydianiline(ODA) as the diamine monomer, 4,4'-(hexafluoroisopropylidene) diphthalic anhydride(6FDA), 4,4'-oxydiphthalic anhydride(ODPA) and 3,3',4,4'- biphenyl tetracarboxylic dianhydride(BPDA) as the dianhydride monomer in N, N-dimethylacetamide. With the increase of 6FDA in the proportion of dianhydride, the tensile strength of the polyimide film showed a decreasing trend. This work provided a high performance film. The mass retention rate at 800°C was above 50%. The glass transition temperatures of the two films were 260 °C and 275 °C. The storage modulus of the two were 1500 MPa and 1250 MPa. The loss modulus were 218.70 MPa and 120.74 MPa. The transmittance of the film was 71.43%. The transmittance of fluorinated copolymerized polyimide films were significantly improved in the visible region of ultraviolet light, indicating that the polyimide film with high transmittance, high tensile strength, high heat resistance and high storage modulus was successfully prepared. It had an excellent application prospect in the field of flexible display.

A series of polyimide (PI) composite films were prepared using PI as matrix and boron nitride (BN) and aluminum nitride (AlN) as the doped phases. The modification of the thermal conductive filler particles was characterized by Fourier transform infrared (FTIR). The results showed that the silane coupling agent KH550 was successfully coated on the surface of BN and AlN. X-ray photoelectron spectrometer characterization was used to further prove that silane coupling agents were successfully attached to BN and AlN surfaces, forming a new chemical bond. Scanning electron microscope (SEM) was used to analyze the dispersion of filler particles in the matrix. It was found that agglomeration phenomenon occurred when the content of BN particles were high, but this problem was improved after the surface modification of BN. The breakdown field strength and volume resistivity of PI/BN composite film increased first and then decreased with the increase of BN content and reached the maximum when the volume fraction of BN was 5%, which was 191.53 kV/mm and 8.832 × 1013 Ω·m, respectively. When the BN content was 9 vol%, the thermal conductivity of the PI/BN composite film was 0.496 W/(m·K), which was 1.4 times larger than that of the pure PI film. The thermal conductivity of the PI/BN/AlN composite film at the BN and AlN contents of 5 vol% and 1 vol%, respectively, is 0.144 W/(m·K) higher than that of 7 vol% PI/BN. It indicated that the synergistic effect of the composite fillers played a significant role, and at the same time, under the premise of ensuring higher thermal conductivity, the amount of thermally conductive particles could be reduced to some extent. After the surface modification of the filler particles, the properties of the composite film showed the same trend compared with the unmodified one, while the only difference was that there was a certain increase in the numerical value.

The dielectric polymer-based films with excellent energy storage properties have been considered as potential candidates for flexible capacitors. In this study, the hierarchical gradient structures...