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With the development of artificial intelligence and machine learning technology, online shopping is increasingly becoming the mainstream shopping method. It is challenging to investigate the correlation between price dispersion and bargaining. In accordance with the assimilation-contrast theory, this study theorizes about the influence of price dispersion on consumers’ bargaining power and it aims to analyze the moderating role of online shopping experience of consumers. Therefore, this paper develops a discrete price model to measure the dispersion of product prices in the marketplace. Cluster analysis was subsequently conducted to preliminary explore the association between price dispersion and bargaining. With the construction of a multiple regression model, the phenomena found by the cluster analysis are further analyzed. The results indicate that the bargaining power of consumers increases with the increase of the price dispersion level. At high levels of the price dispersion, high-experienced consumers exhibit greater bargaining power than low-experienced consumers. At low levels of price dispersion, low-experienced consumers have higher bargaining power than high-experienced consumers. Finally, we demonstrate the validity and robustness of the study results by grouping regressions and replacing four measures of price dispersion.

Al-6.0Mg-0.3Sc alloy deposits are prepared by means of a double-wire arc additive manufacturing process. The formation, porosity, metallographic structure, type of precipitated phase, and mechanica...

Surface functionalization of piezoelectric greatly determines its piezo-catalytic activity and selectivity in that functional group affect specific reactants’ surface adsorption and activation abilities. Herein, we propose chemical functionalization on the surface of nano-scaled BaTiO3 piezoelectric via a one-pot hydrothermal process using polyethylene glycol as surfactant, and evaluate its piezo-catalytic activity and selectivity by degrading model antibiotic and dye reactants under ultrasonic vibrations. Acetate or/and oxalic unidentate ligands on the surface of BaTiO3 nanobelts can be formed by controlling precursor and hydrothermal parameters. Particularly, oxalic acid functionalized BaTiO3 nanobelts presented a high piezo-catalytic rate constant of 0.068 min−1 for Rhodamine B solution and maintained >87% degradation efficiency within 30 min under the condition of ultrasonic bath with 40 kHz and 100 W, which was mainly ascribed to piezo-sensitization effect. This work provides references for the preparation of chemical functionalized catalysts and also contributes to the development of novel catalysts for special applications.

Chimeric antigen receptor (CAR)-T cell therapy is a novel cell therapeutic approach that is increasingly being used to treat patients with relapsed refractory B-cell lymphoma. Despite the efficacy of CAR T cell therapy, it has various adverse effects that can affect any organ in the body. The application of immune checkpoint inhibitors such as programmed death 1 (PD-1), programmed death ligand 1 (PDL-1), and cytotoxic T-lymphocyte antigen 4 (CTLA-4) antibodies has previously been reported to be associated with immune-related adverse events such as thyroid dysfunction and thyroiditis. Reports of immune-related adverse reactions after CAR T therapy are currently extremely rare, with only one case of a cytokine storm (CRS) combined with severe arthritis in a patient with ALL after treatment. Here, we describe two cases of Hashimoto’s thyroiditis secondary to CAR T therapy. Two patients with relapsed refractory diffuse large B-cell lymphoma developed elevated peroxidase and globulin antibodies secondary to CAR-T cell therapy and developed Hashimoto’s thyroiditis. Complete remission was achieved in two patients at 1 and 3 months after CAR-T cell therapy. The inflammation of the thyroid tissue may be directly or indirectly related to CAR T cell therapy, and the mechanisms needs to be further investigated.

Nitrogen (N) cycling microorganisms mediate soil nitrogen transformation processes, thereby affecting agricultural production and environment quality. However, it is not fully understood how active N-cycling microbial community in soil respond to long-term fertilization, as well as which microorganisms regulate soil nitrogen cycling in agricultural ecosystem. Here, we collected the soils from different depths and seasons at a 29-year fertilization experimental field (organic/chemical fertilizer), and investigated the transcriptions of N-cycling functional genes and their contribution to potential nitrification and denitrification. We found that long-term fertilization exerted significant impacts on the transcript abundances of nitrifiers (AOA amoA, AOB amoA and hao) and denitrifiers (narG and nosZ), which was also notably influenced by season variation. The transcriptions of AOA amoA, hao, and narG genes were lowest in autumn, and AOB amoA and nosZ transcript abundances were highest in autumn. Compared to no fertilization, soil potential nitrification rate (PNR) was reduced in fertilization treatments, while soil potential denitrification rate (PDR) was significantly enhanced in organic combined chemical fertilizer treatment. Both PNR and PDR were highest in 0–20 cm among the tested soil depths. Path model indicated active nitrifiers and denitrifiers had significant impact on soil PNR and PDR, respectively. The transcriptions of AOA amoA and nxr genes were significantly correlated with soil PNR (Pearson correlation, r > 0.174, p ). Significant correlation of napA and nosZ transcriptions with soil PDR (Pearson correlation, r > 0.234, p ) was also revealed. Random forest analysis showed that SOC content and soil pH were the important factors explaining the total variance of active nitrifers and denitrifiers, respectively. Taken together, long-term fertilization regimes reduced soil PNR and enhanced PDR, which could be attributed to the different responses of active N-cycling microorganisms to soil environment variations. This work provides new insight into the nitrogen cycle, particularly microbial indicators in nitrification and denitrification of long-term fertilized agricultural ecosystems.

Exposure to veterinary antibiotics (VAs) and preferred as veterinary antibiotics (PVAs) via the food chain is unavoidable for their extensive use not only for treating bacterial infections, but also for use as growth promoters in livestock and aquaculture. One of the consequences is the disturbance of gut microbiota. However, its impact on the virulence and drug resistance of opportunistic pathogens is still unclear. In this study, a total of 26 antibiotics were detected in the urine of 300 young undergraduates in Anhui Province. We found that excessive intake of milk was positively correlated to high levels of VAs and PVAs. It led to the dysbiosis of gut microbiota characterized by high abundance of Bacteroidetes and Proteobacteria. The increase in Proteobacteria was mainly due to a single operational taxonomic unit (OTU) of

Chemodynamic therapy (CDT), an emerging tumor-specific therapeutic modality, is frequently restrained by insufficient intratumoral Fenton catalysts and increasingly inefficient catalysis caused by the continuous consumption of limited H

Recently, the emergent two-dimensional (2D) ferroelectric materials have provided new possibilities for the miniaturization of ferroelectric systems and the integration of novel 2D nano-electronic devices. In addition to the intrinsic ferroelectrics exfoliated from bulk, 2D heterostructures hybridized from electrically non-polarized van der Waals (vdW) materials have also been proven to be a promising platform for the construction of ferroelectricity. Here, we report 30° twisted bilayer–graphene (TBLG) incommensurate moiré superlattice encapsulated by hexagonal boron nitride (h-BN), in which robust hysteretic resistance was detected at the top interface between h-BN and the TBLG from room temperature down to 40 mK. The hysteretic phenomenon can be understood by the extra carrier induced by the interfacial 2D ferroelectric polarization, which is estimated to be around 0.7 pC/m. Our work of interfacial ferroelectric heterostructure achieved by a TBLG/h-BN hybrid system expands the 2D ferroelectric families and opens more possibilities for future coupling the ferroelectricity with rich electronic and optical properties in vdW twistronic devices.

Photodynamic therapy (PDT)-mediated oxidation treatment is extremely attractive for skin melanoma ablation, but the strong hydrophobicity and poor tumor selectivity of photosensitizers, as well as the oxygen-consuming properties of PDT, leading to unsatisfactory therapeutic outcomes. Herein, a tumor acidic microenvironment activatable dissolving microneedle (DHA@HPFe-MN) was developed to realize controlled drug release and excellent chemo-photodynamic therapy of melanoma via oxidative stress amplification. The versatile DHA@HPFe-MN was fabricated by crosslinking a self-synthesized protoporphyrin (PpIX)-ADH-hyaluronic acid (HA) conjugate HA-ADH-PpIX with "iron reservoir" PA-Fe

Due to a powerful DNA damage repair system and a lack of surface markers, there is currently no effective chemotherapy or tailored targeted therapies available for triple-negative breast cancer (TNBC) treatment. Herein, a tailored DNA damage nanoamplifier (Lipo@Nir/Pt(IV)

Numerous studies have addressed the advantages of wire arc additive manufacturing for manufacturing aluminum alloys. However, the role of Ti content in aluminum alloys has rarely been discussed. Herein, the effect of Ti content on the microstructure and properties of Al–7Si–0.6Mg alloys was studied. The alloys were deposited via wire arc additive manufacturing and were examined through optical microscopy (OM), scanning electron microscopy (SEM), and electronic universal testing. The results show that the increase of Ti content gradually promotes the increase of the secondary dendrite arm spacing and also has an increasing tendency to form pores defect in the as-deposited alloys. The change of titanium content also affects the difference between horizontal and vertical direction properties of the alloy. The alloy with a Ti content of 0.112 wt% exhibits the best comprehensive properties. There is no difference in its horizontal and vertical direction properties. The tensile strengths, yield strengths, and elongation of this alloy (T6) along the vertical and horizontal axis are 356 and 355 MPa, 307 and 308 MPa, and 8.5% and 8.0%, respectively.

The room temperature and high temperature tensile properties of Al–7Si–0.6Mg alloy prepared by wire arc additive manufacturing have been investigated. The results show that the strengthening phase ...

The effects of Mg on microstructure, defects and properties of Al–Si alloy deposited by Wire and Arc-based Additive Manufacturing (WAAM) were investigated. The WAAM alloys were characterised by the...

Despite showing considerable potential, wire arc additive manufacturing (WAAM) has been limited to producing Al–Mg alloys. As the addition of Sc can improve the mechanical properties of Al–Mg alloys, in this study, Al–Mg–Sc alloy deposits with different Sc contents were prepared by a WAAM process. The porosity, microstructure, and mechanical properties of the deposits were studied. At Sc contents less than 0.15%, Sc was completely dissolved in the Al matrix without grain refinement, and the mechanical properties were slightly improved. At a Sc content of 0.3%, the primary Al3Sc phase precipitated out of the as-deposited body, resulting in an abrupt change in the microstructure, significant grain refinement, significantly increased tensile strength and yield strength, with a tensile strength, yield strength, and elongation of 372 MPa, 270 MPa, and 22.5%, respectively. Following heat treatment at 350 °C for 1 h, the grain boundaries were refined and the secondary Al3Sc phase was precipitated. Furthermore, the tensile strength and yield strength were significantly increased to 415 MPa and 279 MPa, respectively, and elongation decreased to 18.5%. At a Sc content of 0.45%, due to the aggregated precipitated phase, the coarsened grain boundaries and the limited solid solution amount of Sc in the α(Al) matrix (~ 0.25%), the mechanical properties were not further improved compared with the deposit with Sc content of 0.3%. Thus, based on economic considerations, the optimal Sc content was 0.3%. Owing to their enhanced mechanical properties, WAAM-produced Al–Mg–Sc alloys are expected to have a wide range of applications in aviation, aerospace.

Background Mental health problems among children and adolescents are a pressing public health issue. This study aimed to investigate the associations between screen time (ST), negative life events (NLEs), and emotional and behavioral problems (EBPs) among Chinese children and adolescents. Methods A total of 5959 boys and girls from 14 elementary and junior high schools of four cities in China were included in this study. EBPs were assessed by the Strengths and Difficulties Questionnaire (SDQ), NLEs were evaluated by the Adolescent Self-Rating Life Events Checklist (ASLEC), and ST data were obtained through self-reporting. Descriptive analyses, chi-squared tests, and logistic regression were performed using SPSS 23.0. Results There were significant associations between ST/NLEs and EBPs. Participants with high exposure to ST or NLEs were more likely to have EBPs than those with low exposure to ST or NLEs. The simultaneous associations of ST and NLEs on EBPs were stronger than those of ST or NLEs, individually. Limitations This was a cross-sectional research study; therefore, it could not judge causality or direction. ST and NLEs were retrospective and might have recall biases. Conclusions Our results showed positive associations between ST, NLEs, and EBPs. The results indicate that interventions should be considered to decrease ST and NLEs for children and adolescents.

In this study, an aluminum (Al)–6.3 magnesium (Mg) alloy was fabricated using wire arc additive manufacturing (WAAM), and adopting the cold metal transfer advanced process, with the thermal history...

For the brain computer interface (BCI), it is necessary to collect enough electroencephalography (EEG) signals to train the classification model. When the operation dimension of BCI is large, it will bring great burden to data acquisition. Fortunately, this problem can be solved by our proposed transfer learning method.For the sequential coding experimental paradigm, the multi-band data stitching with label alignment and tangent space mapping (MDSLATSM) algorithm is proposed as a novel heterogeneous transfer learning method. After filtering by multi-band filtering, the artificial signals can be obtained by data stitching from the source domain, which build a bridge between the source domain and target domain. To make the distribution of two domains closer, their covariance matrices are aligned by label alignment. After mapping to the tangent space, the features are extracted from the Riemannian manifold. Finally, the classification results are obtained with feature selection and classification.Our data set includes the EEG signals from 16 subjects. For the heterogeneous transfer learning of cross-label, the average classification accuracy is 78.28%. MDSLATSM is also tested for cross-subject, and the average classification accuracy is 64.01%, which is better than existing methods.Combining multi-band filtering, data stitching, label alignment and tangent space mapping, a novel heterogeneous transfer learning method can be achieved with superior performance, which promotes the practical application of the BCI systems.

Potent and selective ferroptosis regulators promote an intensive understanding of the regulation and mechanisms underlying ferroptosis, which is highly associated with various diseases. In this study, through a stepwise structure optimization, a potent and selective ferroptosis inducer was developed targeting to inhibit glutathione peroxidase 4 (GPX4), and the structure-activity relationship (SAR) of these compounds was uncovered. Compound 26a exhibited outstanding GPX4 inhibitory activity with a percent inhibition up to 71.7% at 1.0 μM compared to 45.9% of RSL-3. At the cellular level, 26a could significantly induce lipid peroxide (LPO) increase and effectively induce ferroptosis with satisfactory selectivity (the value of 31.5). The morphological analysis confirmed the ferroptosis induced by 26a. Furthermore, 26a significantly restrained tumor growth in a mouse 4T1 xenograft model without obvious toxicity.

Exposure to veterinary antibiotics (VAs) and preferred as veterinary antibiotics (PVAs) via the food chain is unavoidable for their extensive use not only for treating bacterial infections, but also for use as growth promoters in livestock and aquaculture. One of the consequences is the disturbance of gut microbiota. However, its impact on the virulence and drug resistance of opportunistic pathogens is still unclear. In this study, a total of 26 antibiotics were detected in the urine of 300 young undergraduates in Anhui Province. We found that excessive intake of milk was positively correlated to high levels of VAs and PVAs. It led to the dysbiosis of gut microbiota characterized by high abundance of Bacteroidetes and Proteobacteria. The increase in Proteobacteria was mainly due to a single operational taxonomic unit (OTU) of Escherichia coli (E. coli). We isolated several E. coli strains from participants and compared their drug resistance and virulence using PCR assay and virulence-related assays. We observed that exposure to high levels of VAs and PVAs induced more resistant genes and drove E. coli strain to become more virulent. At last, we conducted transcriptome analysis to investigate the molecular mechanism of virulent and drug-resistant regulators in the highly virulent E. coli strain. We noted that there were multiple pathways involved in the drug resistance and virulence of the highly virulent strain. Our results demonstrated that participants with high-level VAs and PVAs exposure have a disrupted gut microbiota following the appearance of highly drug-resistant and virulent E. coli and, therefore may be at elevated risk for long-term health complications.

Patients with primary and bone metastatic breast cancer have significantly reduced survival and life quality. Due to the poor drug delivery efficiency of anti-metastasis therapy and the limited response rate of immunotherapy for breast cancer, effective treatment remains a formidable challenge. In this work, engineered macrophages (Oxa(IV)@ZnPc@M) carrying nanomedicine containing oxaliplatin prodrug and photosensitizer are designed as near-infrared (NIR) light-activated drug vectors, aiming to achieve enhanced chemo/photo/immunotherapy of primary and bone metastatic tumors. Oxa(IV)@ZnPc@M exhibits an anti-tumor M1 phenotype polarization and can efficiently home to primary and bone metastatic tumors. Additionally, therapeutics inside Oxa(IV)@ZnPc@M undergo NIR triggered release, which can kill primary tumors via combined chemo-photodynamic therapy and induce immunogenic cell death simultaneously. Oxa(IV)@ZnPc@M combined with anti-PD-L1 can eliminate primary and bone metastatic tumors, activate tumor-specific antitumor immune response, and improve overall survival with limited systemic toxicity. Therefore, this all-in-one macrophage provides a treatment platform for effective therapy of primary and bone metastatic tumors., Bone metastases are associated with poor prognosis in patients with breast cancer and limited therapeutic options. Here the authors exploit near-infrared light responsive macrophages for the tumor-selective delivery of oxaliplatin prodrug for chemo-photodynamic therapy of primary and bone metastatic breast cancer.

Mg/Al layered double hydroxides (LDHs) and the calcined products were prepared and the powders were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), X-ray fluorescence (XRF) and Fourier transform infrared spectrometer (FT-IR). The friction properties of LDHs and the calcined products were tested and the rubbed areas were analyzed by scanning electron microscope, energy disperse spectroscopy (EDS) and auger electron spectrometer (AES). The results showed that the diameter of LDHs was about 100–175 nm and the formula was Mg0.69Al0.31(OH)2(CO3)0.15·0.16H2O. All the calcined products had the laminated structure. The anti-wear properties of 1000 °C calcined products were superior to the LDHs, which was attributed to the supporting and mechanical polishing effects of the hard spinels. The distribution laws of elements of worn area in the horizontal and vertical direction were concluded. The tribological performance of calcined products can be attributed to the “multi-layer self-lubrication mechanisms”. The tribofilms consisted of “carbon-enriched layer”, “oxygen- enriched layer” and “transition layer” and combined strongly with the metal substrate.

With the development of robotics technology, people are gradually inclined to study robots that can imitate human specific behavior, such as writing and drawing robots. At present, there is less research on drawing robots, and the method has certain limitations. This paper designs and completes an innovative drawing method: spiral line method, that is, the method of spiral line superimposing sinusoidal curve to draw. And it is named I-Circle. Compared with the traditional methods, it has the advantages of simple control and strong expressiveness. This work chooses two-dimensional translation platform as hardware system, uses MATLAB to process image and generate path, and uses path coordinate points to generate G code. Then the code is sent to the lower computer through serial port, which controls the two-dimensional translation platform, makes the pen draw automatically on paper, and designs GUI interface, so that the operation process is simple and easy. Through the experiment, we succeeded in drawing pictures, which proved its feasibility. This work can also be expanded, such as replacing the penholder with a micro-drill for sculpture. Similarly, it can be made into cake mounting machine, coffee drawing machine and so on. It can also lay out a drawing robot in a specific place to create drawings on the spot, which can be participated by users, or make the drawing method into software. It has broad application prospects.

Denitrification and dissimilatory nitrate reduction to ammonium (DNRA) influence the nitrate (NO3−) reduction and its final fate in the environment. However, it is unclear how denitrifying and DNRA bacterial communities respond to different environment conditions. Here, we investigated the effects of fertilization and sampling time (April, July and November) on the abundances of nitrogen (N) cycling genes in processes of denitrification and DNRA at different soil depths (0–20, 20–40 and 40–60 cm) based on a long-term fertilization experiment station (initiated in 1987). The abundances of genes involved in NO3− reduction process were determined using quantitative PCR (qPCR) analysis method. Sampling time showed a stronger effect on the abundances of denitrifying and DNRA genes than fertilization. And the effect of fertilization on the abundances of genes involved in NO3− reduction process was decreased with soil depths. Compared with no fertilizer (CK), the application of mineral N fertilizer (N2 and N4) reduced the abundances of denitrification and DNRA genes at 0–20 cm soil depth, regardless of sampling time. However, the application of organic manure combined with mineral N fertilizer (M2N2) clearly increased the abundance of specific denitrifying genes, including napA (NO3− to NO2−) and nosZ (N2O to N2) genes compared with N2 and N4 treatments at 0–20 and 20–40 cm soil depths. Although the abundance of nrfA gene was the highest, the abundance of norB gene was the most sensitive to environmental variation among all the tested N cycling genes. Ratio of NO3− to ammonium (NO3−/NH4+) was significantly correlated with all the denitrifying and DNRA genes. In general, long-term application of organic manure combined with mineral N fertilizer has a potential to mitigate the NO3− leaching and N2O production, and NO3−/NH4+ ratio is an important factor driving the dynamics of bacterial communities involved in the NO3− reduction process.

SummaryObjective Hypertensive disorders of pregnancy (HDP) have been associated with adverse health outcomes for both mothers and children. Previous studies examining associations of maternal thyroid autoantibodies with HDP indicate conflicting results. The objective of this study was to examine associations of maternal thyroid autoantibodies positivity in the first and the second trimesters with the risk of HDP. Design, Participants and Measurements In the Ma'anshan Birth Cohort study, a population-based prospective study in China, a total of 3474 pregnant women were enrolled between May 2013 and September 2014. Thyroid autoantibodies, including anti-thyroperoxidase autoantibody (TPOAb) and anti-thyroglobulin autoantibody (TgAb), as well as thyroid function tests were measured in both the first and the second trimesters in 2893 pregnant women. Multivariate logistic regression analyses were conducted to calculate the odds ratio (OR) and 95% confidence interval (CI) for the associations between thyroid autoantibodies and HDP. Results Multivariate logistic regression analyses showed that TPOAb positivity in the first trimester was associated with a 1.80 (95% CI=1.17-2.78) increased odds of HDP after adjustment for confounders, which was mainly due to an increased risk of gestational hypertension (OR=1.93, 95% CI=1.17-3.18). In addition, TgAb positivity in the first trimester was associated with a higher risk of HDP (OR=1.78, 95% CI=1.16-2.73) after adjustment for confounders, which was mainly due to an increased risk of gestational hypertension (OR=1.89, 95% CI=1.15-3.11). These associations were also seen among euthyroid women. Women with positive TPOAb in the second trimester seemed to have a higher risk of gestational hypertension (OR=1.87, 95% CI=1.02-3.43) after adjustment for confounders. However, among euthyroid women, TPOAb positivity in the second trimester was not associated with HDP. The TgAb status in the second trimester was not associated with HDP. Conclusions Our results show that TPOAb positivity and TgAb positivity in the first trimester are associated with an increased risk of HDP. These data demonstrate that these associations are even seen among euthyroid women. This article is protected by copyright. All rights reserved.

Objective The purpose of this study was to investigate whether isolated maternal hypothyroxinaemia (IMH) is associated with risks of small/large-for-gestational-age (SGA/LGA) infants. Design Population-based prospective cohort study. Setting Ma'anshan Maternal and Child Health (MCH) clinics, China. Population Pregnant women with singleton births (n = 3178). Methods Descriptive statistics were calculated for the demographic characteristics of the mothers and their newborns. Linear regression was applied to estimate the association between thyroid hormone levels and birthweight. Logistic regression was performed to calculate the association between IMH and SGA/LGA. Main outcome measures Outcomes included SGA/LGA. Results The prevalence of IMH, defined as a free thyroxine value (FT4) lower than the 2.5th percentile with normal thyroid stimulating hormone, was 2.5% (78/3080) and 2.5% (74/2999) in the first and second trimesters, respectively. Additionally, 306 (9.6%) and 524 (16.5%) infants were defined as SGA and LGA, respectively. No evidence supported the notion that IMH is associated with an increased risk for SGA in either the first [odds ratio (OR): 1.762, 95% confidence interval (CI): 0.759-4.089] or the second (OR: 0.763, 95% CI: 0.231-2.516) trimester. However, an increased risk of LGA was observed among IMH women in the second trimester (OR: 2.088, 95% CI: 1.193-3.654). Maternal TPO-Ab positivity in the second trimester increased the risk of SGA (OR: 2.094, 95% CI: 1.333-3.290). Conclusion This study provides evidence that IMH is associated with LGA. Funding This work was supported by the National Natural Science Foundation of China (No. 81330068). Tweetable abstract Isolated maternal hypothyroxinaemia may increase the risk of large-for-gestational-age infants.

The coexistence of blowout and lost circulation in multi-pressure fractured reservoirs has always been a huge challenge to the oil industry. Although the use of high-density kill fluids can ensure the safety of well control, the problem of lost circulation in low pressure layer is still troublesome. Gel is widely used as a temporary plugging system, but the conventional gel plugging system will float when used in combination with high-density kill fluid, resulting in failure of temporary plugging. In this paper, a novel high-density bromide-based nanocomposite gel (HDGEL) was developed, the gel formation mechanism was explored, and its performance was evaluated in the laboratory. The gel is weighted by sodium bromide (NaBr), and cross-linked by covalent bonds, density 1.2–1.5 g/cm3 adjustable, and its temperature resistance can reach 160 °C. Rheological tests show that the gel solution has low initial viscosity and easy to pump. The gelation time can be adjusted from 8 to 12 h, which can be directly broken by the drill or regular jetting nozzle and then flowed back. It can be used in combination with high-density kill fluid to ensure temporary plugging effect. In the fractures with tip sizes (0.014 cm), the maximum bearing pressure of HDGEL is 17.52 MPa, and the regained-permeability recovery can reach 86.81% without the use of gel breaker. This paper introduces a new gel system for multi-pressure reservoirs that can be used in combination with high-density kill fluid and makes recommendations for its engineering application.

In this work, a simple and efficient dispersive solid-phase microextraction (DSPME) method based on magnetic dummy molecularly imprinted polymer nanoparticles (MMIPs) was developed for the extraction of five phthalate monoesters (mPAEs) from human urine samples. The MMIPs synthesized by sol–gel reaction and surface imprinting were analyzed by transmission electron microscopy, scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, vibrating sample magnetometry, and thermogravimetric analysis. The obtained results demonstrate that the MMIPs prepared herein are characterized by high selectivity, good adsorption capacity (124.5 mg/g), excellent reusability (over five sorption–desorption cycles), and fast adsorption rates (about 30 min to equilibrium) with respect to five mPAEs. In addition, the MMIPs can be easily separated from the sample solutions due to their good magnetic susceptibility (34.0 emu/g). Using MMIPs as sorbent material in DSPME, five mPAEs in three human urine samples were extracted, and then analyzed by high-performance liquid chromatography (HPLC). Based on the obtained results, this method shows good linearity in the range of 1–100 mg/L for monomethyl phthalate, monoethyl phthalate, and monobutyl phthalate, in the range of 1–80 mg/L for monobenzyl phthalate, and in the range of 1–50 mg/L for monoethylhexyl phthalate. Moreover, good recovery (80.0%–101.0%) of all five mPAEs was observed at three spiked level with relative standard deviations of 0.6–6.6%. Overall, the results reported herein indicate that the prepared MMIPs can be used as sorbent material for the dispersive solid-phase microextraction of phthalate monoesters in human urine samples.

Atomic force microscopy (AFM) is a commonly used technique for graphene thickness measurement. However, due to surface roughness caused by graphene itself and variation introduced in AFM measurement, graphene thickness is difficult to be accurately determined by AFM. In this paper, a histogram method was used for reliable measurements of graphene thickness using AFM. The influences of various measurement parameters in AFM analysis were investigated. The experimental results indicate that significant deviation can be introduced using various order of flatten and improperly selected measurement parameters including amplitude setpoint and drive amplitude. At amplitude setpoint of 100 mV and drive amplitude of 100 mV, thickness of 1 layer (1L), 2 layers (2L) and 4 layers (4L) graphene were measured. The height differences for 1L, 2L and 4L were 1.51 ± 0.16 nm, 1.92 ± 0.13 nm and 2.73 ± 0.10 nm, respectively. By comparing these values, thickness of single layer graphene can be accurately determined to be 0.41 ± 0.09 nm.

In utero exposure to phthalates may have adverse effects on pregnant women and their offsprings. Therefore, the exposure level of these substances among individuals, particularly among sensitive population, is of concern. The objective of the present study is to characterize urinary concentrations of phthalate metabolites at multiple time points during pregnancy in Chinese women. A total of 3455 pregnant women were included from Ma'anshan Birth Cohort in China. Spot urine samples in the morning (8:00–10:00) and questionnaires were obtained at three separate visits (approximately in 10, 26, and 34 gestational weeks). Seven phthalate metabolites from urine samples were analyzed, including monomethyl phthalate (MMP), monoethyl phthalate (MEP), monobutyl phthalate (MBP), mono benzyl phthalate (MBzP), mono-2-ethylhexyl phthalate (MEHP), mono (2-ethyl-5-oxohexyl) phthalate (MEOHP) and mono (2-ethyl-5-hydroxyhexyl) phthalate (MEHHP). Geometric means of concentrations were ranged from 0.05 to 41.0 ng/mL for all the metabolites mentioned above. No individual exposure level was above the 95th percentiles for all the seven phthalates. On the three separate visits, 0.5%, 0.9% and 1.2% of the participants had coexposure to above the 75th percentiles for all metabolites. Taken these visits together, a total of 29 urine samples had concentrations above the 95th percentiles, while 3.0%–5.6% of urine levels were above 75th percentiles for at least one specific phthalate metabolite. We observed moderate intraclass correlation coefficients (ICCs) ranging from 0.44 to 0.56 for MBzP, MEHP and MEP, and lower ICCs, from 0.28 to 0.32, for MMP, MBP, MEOHP and MEHHP. Sampling season was associated with concentrations of all phthalate metabolites, showing heavier exposure was more likely to occur during summer. In summary, phthalate exposure is prevalent in Chinese pregnant women. However, throughout pregnancy coexposure to multiple phthalates at the upper percentile of exposure is infrequent. Mild to moderate temporal stability indicates that a single measurement in spot urine collected in the morning (8:00–10:00) seems not enough to describe throughout pregnancy phthalate exposure. Urinary levels vary by sampling seasons, which should be taken into consideration in future analyses. Keywords: Phthalate metabolites, Pregnant women, Birth cohort, Repeated measure analysis, China

The use of two-dimensional materials could thin down electronic devices to atomic layers, a regime where the precise control of electronic transport becomes a great challenge. A single layer of the ferromagnetic semiconductor CrI${}_{3}$ has an electronic structure that is significantly modulated by noncollinear magnetization. By introducing a ferromagnetic domain wall, a one-dimensional conduction channel just a few nanometers wide can be formed in the insulating monolayer. These conducting wires can be spatially relocated, ``rewritten'', by applying a magnetic field or injecting spin waves, suggesting reprogrammable electronic nanodevices.

A multiferroic BiFeO3 (BFO) catalyst was fabricated through a mild one-pot hydrothermal process with a bath-ultrasound assisted dissolution of Fe(NO3)3·9H2O for 30 min. X-ray photoemission spectroscopy revealed that the BFO (BFO-u) catalyst with US assisted dissolution of Fe(NO3)3·9H2O in the synthetic process exhibited high Fe2+ and OH− levels, which could be explained to be Fe3+ + H2O → ) ) ) Fe2+ + H+ + •OH. As a result, BFO-u catalyst activated potassium peroxymonosulfate (PMS) efficiently for degrading tetracycline hydrochloride. In particular, visible-light assisted activation of PMS over BFO-u catalyst exhibited the highest degradation rate constant, at 0.352 min−1. Species-trapping experiments revealed that the presence of PMS promoted the generation of •OH, •O2− and 1O2 that all participated in degrading TCH, in which 1O2 was primarily contributed to the degradation. Also, BFO-u catalyst was stable and recyclable and thus suitable for practical applications.