Spatial association network of PM2.5 and its influencing factors in the Beijing-Tianjin-Hebei urban agglomeration.

In this paper, we empirically study the spatial association network of PM2.5 and the factors influencing those correlations using the gravity model, social network analysis (SNA), and the quadratic assignment procedure (QAP) based on data from the Beijing-Tianjin-Hebei urban agglomeration (BTHUA) in China from 2005 to 2018. We draw the following conclusions. First, the spatial association network of PM2.5 exhibits relatively typical network structure characteristics: the network density and network correlations are highly sensitive to efforts to control air pollution, and there are obvious spatial correlations within the network. Second, cities in the center of the BTHUA have large network centrality values, while cities in the peripheral region have small centrality values. Tianjin is a core city in the network, and the spillover effect of PM2.5 pollution in Shijiazhuang and Hengshui is the most noticeable. Third, the 14 cities can be divided into four plates, with each plate having obvious geographical location characteristics and linkage effects. The cities in the association network are divided into three tiers. Beijing, Tianjin, and Shijiazhuang are located in the first tier, and a considerable number of PM2.5 connections are completed through these cities. Fourth, differences in geographical distance and urbanization are the main drivers of the spatial correlations of PM2.5. The greater the urbanization differences, the more likely the generation of PM2.5 links is, while the opposite is true for differences in geographical distance.

Low-Coordinated Zn-N2 Sites as Bidirectional Atomic Catalysis for Room-Temperature Na-S Batteries.

The rational design of advanced catalysts for sodium-sulfur (Na-S) batteries is important but remains challenging due to the limited understanding of sulfur catalytic mechanisms. Here, we propose an efficient sulfur host consisting of atomic low-coordinated Zn-N2 sites dispersed on N-rich microporous graphene (Zn-N2@NG), which realizes state-of-the-art sodium-storage performance with a high sulfur content of 66 wt %, high-rate capability (467 mA h g-1 at 5 A g-1), and long cycling stability for 6500 cycles with an ultralow capacity decay rate of 0.0062% per cycle. Ex situ methods combined with theoretical calculations demonstrate the superior bidirectional catalysis of Zn-N2 sites on sulfur conversion (S8 ↔ Na2S). Furthermore, in situ transmission electron microscopy was applied to visualize the microscopic S redox evolution under the catalysis of Zn-N2 sites without liquid electrolytes. During the sodiation process, both surface S nanoparticles and S molecules in the mircopores of Zn-N2@NG quickly convert into Na2S nanograins. During the following desodiation process, only a small part of the above Na2S can be oxidized into Na2Sx. These results reveal that, without liquid electrolytes, Na2S is difficult to be decomposed even with the assistance of Zn-N2 sites. This conclusion emphasizes the critical role of liquid electrolytes in the catalytic oxidation of Na2S, which was usually ignored by previous works.

A volatile microemulsion method of preparing water-soluble photo-absorbers for 3D printing of high-resolution, high-water-content hydrogel structures.

Digital light processing (DLP)-based three-dimensional (3D) printing is an ideal tool to manufacture hydrogel structures in complex 3D forms. Using DLP to print hydrogel structures with high resolution requires the addition of water-soluble photo-absorbers to absorb excess light and confine photopolymerization to the desired area. However, the current photo-absorbers for hydrogel printing are neither efficient to absorb the excess light nor water-soluble. Herein, we report a volatile microemulsion template method that converts a wide range of commercial non-water-soluble photo-absorbers including Sudan orange G, quercetin, and many others to water-soluble nanoparticles with solubility above 1.0 g mL-1. After using these water-soluble photo-absorber nanoparticles, the highest lateral and vertical resolutions of printing high-water-content (70-80 wt%) hydrogels can be improved to 5 µm and 20 µm, respectively. Moreover, the quercetin nanoparticle can be easily washed out so that we achieve colorless and transparent printed hydrogel structures with excellent mechanical deformability and biocompatibility as well as thermally controllable variations on transparency and actuation. The proposed methods pave a new efficient way to develop water-soluble photo-absorbers, which helps to greatly improve the printing resolution of the high-water-content hydrogel structure and would be beneficial to extend the application scope of hydrogels.

Multimaterial 3D printed self-locking thick-panel origami metamaterials.

Thick-panel origami has shown great potential in engineering applications. However, the thick-panel origami created by current design methods cannot be readily adopted to structural applications due to the inefficient manufacturing methods. Here, we report a design and manufacturing strategy for creating thick-panel origami structures with excellent foldability and capability of withstanding cyclic loading. We directly print thick-panel origami through a single fused deposition modeling (FDM) multimaterial 3D printer following a wrapping-based fabrication strategy where the rigid panels are wrapped and connected by highly stretchable soft parts. Through stacking two thick-panel origami panels into a predetermined configuration, we develop a 3D self-locking thick-panel origami structure that deforms by following a push-to-pull mode enabling the origami structure to support a load over 11000 times of its own weight and sustain more than 100 cycles of 40% compressive strain. After optimizing geometric parameters through a self-built theoretical model, we demonstrate that the mechanical response of the self-locking thick-panel origami structure is highly programmable, and such multi-layer origami structure can have a substantially improved impact energy absorption for various structural applications.

Self-Powered Wireless Flexible Ionogel Wearable Devices.

Ionogels are promising soft materials for flexible wearable devices because of their unique features such as ionic conductivity and thermal stability. Ionogels reported to date show excellent sensing sensitivity; however, they suffer from a complicated external power supply. Herein, we report a self-powered wearable device based on an ionogel incorporating poly(vinylidene fluoride) (PVDF). The three-dimensional (3D) printed PVDF-ionogel exhibits amazing stretchability (1500%), high conductivity (0.36 S/m at 105 Hz), and an extremely low glass transition temperature (-84 °C). Moreover, the flexible wearable devices assembled from the PVDF-ionogel can precisely detect physiological signals (e.g., wrist, gesture, running, etc.) with a self-powered supply. Most significantly, a self-powered wireless flexible wearable device based on our PVDF-ionogel achieves monitoring healthcare of a human by transmitting obtained signals with a Bluetooth module timely and accurately. This work provides a facile and efficient method for fabricating cost-effective wireless wearable devices with a self-powered supply, enabling their potential applications for healthcare, motion detection, human-machine interfaces, etc.

A semiautomatic segmentation method framework for pelvic bone tumors based on CT-MR multimodal images.

The pelvic structure is complex and the tumor is poorly defined from the surrounding tissues. Finding the exact tumor resection margin based on the surgeon's clinical experience alone is a time-consuming and difficult task, which is a major factor leading to surgical failure. An accurate method for segmenting pelvic bone tumors is needed. In this paper, a semiautomatic segmentation method for pelvic bone tumors based on CT-MR multimodal images is presented. The method combines multiple medical prior knowledge and image segmentation algorithms. Finally, the segmentation results are visualized in three dimensions. We tested the proposed method on a collection of 10 cases (97 tumor MR images in total). The segmentation results were compared with the manual annotation of the physicians. On average, our method has an accuracy of 0.9358, a recall of 0.9278, an IOU value of 0.8697, a Dice value of 0.9280, and an AUC value of 0.9632. The average error of the 3D model was within the allowable range of the surgery. The proposed algorithm can accurately segment bone tumors in pelvic MR images regardless of tumor location, size, and other factors. It provides the possibility to assist pelvic bone tumor preservation surgery.

Comparison of copper and graphene-assembled films in 5G wireless communication and THz electromagnetic-interference shielding.

Since first developed, the conducting materials in wireless communication and electromagnetic interference (EMI) shielding devices have been primarily made of metal-based structures. Here, we present a graphene-assembled film (GAF) that can be used to replace copper in such practical electronics. The GAF-based antennas present strong anticorrosive behavior. The GAF ultra-wideband antenna covers the frequency range of 3.7 GHz to 67 GHz with the bandwidth (BW) of 63.3 GHz, which exceed ~110% than the copper foil-based antenna. The GAF Fifth Generation (5G) antenna array features a wider BW and lower sidelobe level compared with that of copper antennas. EMI shielding effectiveness (SE) of GAF also outperforms copper, reaching up to 127 dB in the frequency range of 2.6 GHz to 0.32 THz, with a SE per unit thickness of 6,966 dB/mm. We also confirm that GAF metamaterials exhibit promising frequency selection characteristics and angular stability as flexible frequency selective surfaces.

Multimaterial Three-Dimensional Printing of Ultraviolet-Curable Ionic Conductive Elastomers with Diverse Polymers for Multifunctional Flexible Electronics.

Ionic conductive elastomers (ICEs) are emerging stretchable and ionic conductive materials that are solvent-free and thus demonstrate excellent thermal stability. Three-dimensional (3D) printing that creates complex 3D structures in free forms is considered as an ideal approach to manufacture sophisticated ICE-based devices. However, the current technologies constrain 3D printed ICE structures in a single material, which greatly limits functionality and performance of ICE-based devices and machines. Here, we report a digital light processing (DLP)-based multimaterial 3D printing capability to seemly integrate ultraviolet-curable ICE (UV-ICE) with nonconductive materials to create ionic flexible electronic devices in 3D forms with enhanced performance. This unique capability allows us to readily manufacture various 3D flexible electronic devices. To demonstrate this, we printed UV-ICE circuits into polymer substrates with different mechanical properties to create resistive strain and force sensors; we printed flexible capacitive sensors with high sensitivity (2 kPa-1) and a wide range of measured pressures (from 5 Pa to 550 kPa) by creating a complex microstructure in the dielectric layer; we even realized ionic conductor-activated four-dimensional (4D) printing by printing a UV-ICE circuit into a shape memory polymer substrate. The proposed approach paves a new efficient way to realize multifunctional flexible devices and machines by bonding ICEs with other polymers in 3D forms.

Molecular Features, Prognostic Value, and Cancer Immune Interactions of Angiogenesis-Related Genes in Ovarian Cancer.

Angiogenesis is crucial to tumor growth and metastasis; it plays a key role in various cancers development and progression. However, the potential effects of angiogenesis-related genes (ARGs) in ovarian cancer (OC) remain to be further investigated. We discussed the characteristics changes of ARGs in 784 OC samples from genomic and transcriptional levels, as well as their expression patterns based on four distinct datasets. First, 784 OC patients were divided into three molecular subtypes, and the findings indicated that ARG changes were correlated with clinicopathological parameters, prognosis, and immune cell-infiltrating tumor microenvironment (TME). OC patients were subsequently divided into two gene subtypes depending on differentially expressed genes (DEGs) of the abovementioned molecular subtypes. We also established an ARGs-related score (ARGs score) model for evaluating overall survival (OS) and determining the immunological landscape of OC patients, therefore predicting patients' prognosis and therapeutic responses. A lower ARGs' score accompanied by a high mutation frequency implies a higher probability of survival. Furthermore, the ARG score was correlated with the cancer stem cell (CSC) index and chemotherapeutic sensitivity. The significant involvement of ARGs in the tumor-immune-stromal microenvironment, clinicopathological characteristics, and prognosis were established in our systematic investigation of ARGs for OC patients. These discoveries might help us to better understand the role of ARGs in OC, as well as give new insight for predicting the prognosis and providing promising immunotherapy.

Centrifugal multimaterial 3D printing of multifunctional heterogeneous objects.

There are growing demands for multimaterial three-dimensional (3D) printing to manufacture 3D object where voxels with different properties and functions are precisely arranged. Digital light processing (DLP) is a high-resolution fast-speed 3D printing technology suitable for various materials. However, multimaterial 3D printing is challenging for DLP as the current multimaterial switching methods require direct contact onto the printed part to remove residual resin. Here we report a DLP-based centrifugal multimaterial (CM) 3D printing method to generate large-volume heterogeneous 3D objects where composition, property and function are programmable at voxel scale. Centrifugal force enables non-contact, high-efficiency multimaterial switching, so that the CM 3D printer can print heterogenous 3D structures in large area (up to 180 mm × 130 mm) made of materials ranging from hydrogels to functional polymers, and even ceramics. Our CM 3D printing method exhibits excellent capability of fabricating digital materials, soft robots, and ceramic devices.

Comparison of the clinical outcomes after esophagectomy between intrathoracic anastomosis and cervical anastomosis: a systematic review and meta-analysis.

OBJECTIVES: Esophageal cancer is a high-mortality disease. Esophagectomy is the most effective method to treat esophageal cancer, accompanied with a high incidence of post-operation complications. The anastomosis has a close connection to many severe post-operation complications. However, it remains controversial about the choice of intrathoracic anastomosis (IA) or cervical anastomosis (CA). The study was conducted to compare the clinical outcomes between the two approaches. METHODS: We searched databases for both randomized controlled trials (RCTs) and cohort studies comparing post-operation outcomes between IA and CA. Primary outcomes were the incidences of anastomotic leakage and mortality. Secondary outcomes were the incidences of anastomotic stenosis, pneumonia and re-operation. RESULTS: Twenty studies with a total of 7,479 patients (CA group: n = 3,183; IA group: n = 4296) were included. The results indicated that CA group had a higher incidence of anastomotic leakage than IA group (odds ratio [OR] = 2.05, 95% confidence intervals [CI] = 1.61-2.60, I2 = 53.31%, P < 0.01). Subgroup analyses showed that CA group had higher incidences of type I (OR = 2.19, 95%CI = 1.05-4.57, I2 = 0.00%, P = 0.04) and type II (OR = 2.75, 95%CI = 1.95-3.88, I2 = 1.80%, P < 0.01) anastomotic leakage than IA group. No difference was found in type III anastomotic leakage (OR = 1.23, 95%CI = 0.82-1.86, I2 = 20.92%, P = 0.31). The 90-day mortality (OR = 1.66, 95%CI = 1.11-2.47, I2 = 0.0%, P = 0.01) in IA group were lower than that in CA group. No difference was found in in-hospital mortality (OR = 1.31, 95%CI = 0.91-1.88, I2 = 0.00%, P = 0.15) and 30-day mortality (OR = 1.08, 95%CI = 0.69-1.70, I2 = 0.00%, P = 0.74). CONCLUSIONS: IA might be a better anastomotic approach than CA, with a lower incidence of anastomosis leakage and no increase in short-term mortality. Significant heterogeneity and publication bias might limit the reliability of the results. More high-quality studies are needed to verify and update our findings.

Based on 16 S rRNA sequencing and metabonomics to reveal the new mechanism of aluminum potassium sulfate induced inflammation and abnormal lipid metabolism in mice.

More and more discoveries have been made about the chronic toxic effects of aluminum, but the specific mechanism of action remains unclear. In this study, we explored the perturbation of aluminum on intestinal microflora and its effects on host and microbial metabolites through a more realistic nutrient absorption model. The microorganisms Turicibacter, Lactobacillus murinus, Lactobacillus_reuteri and Bifidobacterium pseudolongum may be the main targets of the aluminum affecting microbiota. Lysine, proline, putrescine, serotonin and cholesterol may be important metabolites affected by aluminum ions after the interference of intestinal flora composition, leading to abnormal metabolism pathways of amino acids and lipids in the body, and thus promoting inflammation and lesion. The possible mechanisms of aluminum action on the body: (1) Affecting immune cell response, ROS generation and production of a series of pro-inflammatory factors to promote inflammation; (2) Through the disturbance of intestinal microbiota composition structure, change the abundance of metabolites, and then affect amino acid metabolism, lipid metabolism pathways. The joint analysis of multiple omics showed significant difference in microbiome abundance and metabolomics expression between high dose group and the control group.

Lactobacillus johnsonii alleviates colitis by TLR1/2-STAT3 mediated CD206+ macrophagesIL-10 activation.

Imbalance of gut microbiota homeostasis is related to the occurrence of ulcerative colitis (UC), and probiotics are thought to modulate immune microenvironment and repair barrier function. Here, in order to reveal the interaction between UC and gut microbiota, we screened a new probiotic strain by 16S rRNA sequencing from Dextran Sulfate Sodium (DSS)-induced colitis mice, and explored the mechanism and clinical relevance. Lactobacillus johnsonii (L. johnsonii), as a potential anti-inflammatory bacterium was decreased colonization in colitis mice. Gavage L. johnsonii could alleviate colitis by specifically increasing the proportion of intestinal macrophages and the secretion of Il-10 with macrophages depleted model and in Il10-/- mice. We identified this subset of immune cells activated by L. johnsonii as CD206+ macrophagesIL-10. Mechanistically, L. johnsonii supplementation enhanced the mobilization of CD206+ macrophagesIL-10 through the activation of STAT3 in vivo and in vitro. In addition, we revealed that TLR1/2 was essential for the activation of STAT3 and the recognition of L. johnsonii by macrophages. Clinically, there was positive correlation between the abundance of L. johnsonii and the expression level of MRC1, IL10 and TLR1/2 in UC tissues. L. johnsonii could activate native macrophages into CD206+ macrophages and release IL-10 through TLR1/2-STAT3 pathway to relieve experimental colitis. L. johnsonii may serve as an immunomodulator and anti-inflammatory therapeutic target for UC.

Effect of Silicon Source (Fly Ash, Silica Dust, Gangue) on the Preparation of Porous Mullite Ceramics from Aluminum Dross.

Aluminum dross (AD) is a waste product produced during aluminum processing and can be used to prepare mullite ceramic materials. However, the research on the preparation of mullite porous ceramics entirely from solid waste is still in the development stage. In this paper, porous mullite ceramics were successfully fabricated using a solid-phase sintering process with AD and different silicon sources (fly ash, silica dust, and gangue) as raw materials. The bulk density, apparent porosity, and compressive strength of the specimens were obtained, and the phase compositions and microstructures of the sintered specimens were measured using XRD and SEM, respectively. The average activation energy of the phase transition of fly ash, silica dust, and gangue as silicon sources were 984 kJ/mol, 1113 kJ/mol, and 741 kJ/mol, respectively. The microstructures of the mullite in the specimens were prisms, random aggregates, and needle-shaped, respectively. The formation of needle-shaped mullite combined with the substrate enhanced the mechanical strength of the porous mullite ceramics. The apparent porosity, density, and compressive strength of the specimens with gangue as the silicon source were 33.13%, 1.98 g/cm3, and 147.84 MPa, respectively, when sintered at 1300 °C for 2 h.

Analysis of the Spatial Association Network of PM2.5 and Its Influencing Factors in China.

The spatial association network of PM2.5 is constructed using a modified gravity model, with the data of 31 provinces in China from 2009-2020. On this basis, the spatial correlation structure of PM2.5 and its influencing factors were investigated through social network analysis (SNA). The results showed that, first, the PM2.5 has a typical and complex spatial correlation, and the correlation degree tends to decrease with the implementation of collaborative management. Second, they show that there is a clear "core-edge" distribution pattern in the network. Some areas with serious PM2.5 pollution have experienced different degrees of decline in centrality due to policy pressure. Third, the network is divided into "net benefits", "net spillovers", "two-way spillovers" and "brokers". The linkage effect among the four blocks is obvious. Fourth, the government intervention and the industrial structure differentiation promote the formation of the network, but environmental regulation and car ownership differentiation have the opposite effect on the network.

Efficacy of endoscopic ultrasound in the evaluation of small gastrointestinal stromal tumors.

BACKGROUND: Gastrointestinal stromal tumors (GISTs) with a diameter of < 2 cm are called small GISTs. Currently, endoscopic ultrasound (EUS) is widely used as a regular follow-up method for GISTs, which can also provide a preliminary basis for judging the malignancy potential of lesions. However, there are no studies on the accuracy of EUS to assess the malignant potential of small GISTs. AIM: To evaluate the efficacy of EUS in the diagnosis and risk assessment of small GISTs. METHODS: We collected data from patients with small GISTs who were admitted to Shengjing Hospital of China Medical University between October 2014 and July 2019. The accurate diagnosis and risk classifications of patients were based on the pathological assessment according to the modified National Institute of Health criteria after endoscopic resection or laparoscopic surgery. Preoperative EUS features (marginal irregularity, cystic changes, homogeneity, ulceration, and strong echogenic foci) were retrospectively analyzed. The assessment results based on EUS features were compared with the pathological features. RESULTS: A total of 256 patients (69 men and 187 women) were enrolled. Pathological results included 232, 16, 7, and 1 very low-, low-, intermediate-, and high-risk cases, respectively. The most frequent tumor location was the gastric fundus (78.1%), and mitoses were calculated as > 5/50 high power field in 8 (3.1%) patients. Marginal irregularity, ulceration, strong echo foci, and heterogeneity were detected in 1 (0.4%), 2 (0.8%), 22 (8.6%), and 67 (65.1%) patients, respectively. However, cystic changes were not detected. Tumor size was positively correlated with the mitotic index (P < 0.001). Receiver operating curve analysis identified 1.48 cm as the best cut-off value to predict malignant potential (95% confidence interval: 0.824-0.956). EUS heterogeneity with tumor diameters > 1.48 cm was associated with higher risk classification (P < 0.05). CONCLUSION: Small GISTs (diameters > 1.48 cm) with positive EUS features should receive intensive surveillance or undergo endoscopic surgery. EUS and dissection are efficient diagnostic and therapeutic approaches for small GISTs.

Broadband Insulator-Based Dynamic Diode with Ultrafast Hot Carriers Process.

The excitation, rebound, and transport process of hot carriers (HCs) inside dynamic diode (DD) based on insulators has been rarely explored due to the original stereotyped in which it was thought that the insulators are nonconductive. However, the carrier dynamics of DD is totally different from the static diode, which may bring a subverting insight of insulators. Herein, we discovered insulators could be conductive under the framework of DD; the HC process inside the rebounding procedure caused by the disappearance and reestablishment of the built-in electric field at the interface of insulator/semiconductor heterostructure is the main generation mechanism. This type of DD can response fast up to 1 µs to mechanical excitation with an output of ~10 V, showing a wide band frequency response under different input frequencies from 0 to 40 kHz. It can work under extreme environments; various applications like underwater communication network, self-powered sensor/detector in the sea environment, and life health monitoring can be achieved.

Electrical Tree Characteristics of Bisphenol A Epoxy Resin/Maleopimaric Anhydride Curing System.

Epoxy resin insulation materials are mainly derived from petrochemical materials which have the disadvantages of resource consumption and environmental pollution. In order to cure bisphenol A epoxy resin, a maleopimaric anhydride (MPA) curing agent was prepared from rosin, a renewable resource, and blended with a petroleum-based curing agent (methylhexahy-drophthalic anhydride). The influence of maleopimaric anhydride content on the initiation and growth characteristics of electrical trees was studied and analyzed in this paper using molecular dynamics simulation (MD) and electrical tree tests at an 18-kilovolt power frequency voltage. When the MPA content used was ≤10%, the free volume percentage of the curing system increased with MPA content, and thus the initiation voltage became lower; when the MPA content was ≥20%, the hydrogenated phenanthrene ring structure content increased significantly with increasing MPA content, and the rigidity of the curing system increased significantly; thus, the initiation voltage gradually increased. MPA4 had an 11.11% higher initiation voltage than the petroleum-based control group. The effect of the polar rigid structure within the curing system significantly inhibited the growth rate and length of electrical trees as MPA content increased. Electrical trees developed into light-colored, thin, and narrow dendritic structures when the MPA content reached 40%. The results show that curing epoxy resin with the rosin-based curing agent maleopimaric anhydride (MPA), in place of a petroleum-based curing agent, can produce environmentally friendly resins with excellent electrical tree resistance and potential application prospects.

Proteotranscriptomic Integration analyses reveals new mechanistic insights regarding Bombyx mori fluorosis.

The commercial value of silkworms has been widely explored and the effects of fluoride exposure on silkworms' breeding and silk production cannot be ignored. Bombyx mori is a commonly used model to explore the mechanisms of fluorosis. In the present study, we analyzed the differences in physiological and biochemical indicators after exposing larva to NaF, then evaluated differential genes and proteins. Compared to control, larvae exposed to 600 mg L-1 NaF presented decreased bodyweight, damaged midgut tissue, and were accompanied by oxidative stress. The RNA-seq showed 1493 differentially expressed genes (574 upregulated and 919 downregulated). Meanwhile, the TMT detected 189 differentially expressed proteins (133 upregulated and 56 downregulated). The integrative analysis led to 4 upregulated and 9 downregulated genes and proteins. Finally, we hypothesized that fluoride exposure might affect the intestinal digestion of silkworms, inhibit the gene expression of detoxification enzymes and stimulate cellular immune responses. Our current findings provided new insights into insect fluorosis.