The degree of risk factor and accumulation effect for large niche in individuals after cesarean section.

BACKGROUND: The risk factors associated with niche on the cesarean scar have been reported, however, the degree of these factors associated with large niche and the accumulation effects of these risk factors on the development of large niche are unclear. METHODS: Large niche was evaluated by transvaginal sonography during mid-follicular phase. Logistic regression model was used to assess 32 risk factors by univariate analysis. Then, a scoring model based on the screened risk factors was generated. The performance of this model was evaluated by area under curve (AUC). Finally, the scoring model was applied in 123 women to assess the external validation. RESULT(S): In the training cohort study, 163 women were diagnosed with large niche. The final scoring model involves eight risk factors with the rating scores including age at delivery (30-34 years: 1 point; ≥ 35 years: 4.5 points), retroflexed uterus (8.5 points), meconium-stained amniotic fluid (4.5 points), twice CSs (4.0 points), postpartum endometritis (4.5 points), premature rupture of membranes (2.5 points), intrahepatic cholestasis of pregnancy (mild to moderate: 3 points; severe: 6.5 points), and cervical dilatation (1-3 cm: 2.0 points; 4-10 cm: 4.5 points). The accumulation effect with a cut-off value of 8.0 in the scoring was associated with the large niche after CS. CONCLUSION(S): This is the first scoring model to objectively quantify the risk of a large niche after CS. Optimal risk factors control by avoiding high score factors and multiple factors accumulation may eliminate the risk of large niche development.

Fatigue Driving Detection Method Based on Combination of BP Neural Network and Time Cumulative Effect.

Fatigue driving has always received a lot of attention, but few studies have focused on the fact that human fatigue is a cumulative process over time, and there are no models available to reflect this phenomenon. Furthermore, the problem of incorrect detection due to facial expression is still not well addressed. In this article, a model based on BP neural network and time cumulative effect was proposed to solve these problems. Experimental data were used to carry out this work and validate the proposed method. Firstly, the Adaboost algorithm was applied to detect faces, and the Kalman filter algorithm was used to trace the face movement. Then, a cascade regression tree-based method was used to detect the 68 facial landmarks and an improved method combining key points and image processing was adopted to calculate the eye aspect ratio (EAR). After that, a BP neural network model was developed and trained by selecting three characteristics: the longest period of continuous eye closure, number of yawns, and percentage of eye closure time (PERCLOS), and then the detection results without and with facial expressions were discussed and analyzed. Finally, by introducing the Sigmoid function, a fatigue detection model considering the time accumulation effect was established, and the drivers' fatigue state was identified segment by segment through the recorded video. Compared with the traditional BP neural network model, the detection accuracies of the proposed model without and with facial expressions increased by 3.3% and 8.4%, respectively. The number of incorrect detections in the awake state also decreased obviously. The experimental results show that the proposed model can effectively filter out incorrect detections caused by facial expressions and truly reflect that driver fatigue is a time accumulating process.

Charge-Accumulation Effect in Transition Metal Dichalcogenide Heterobilayers.

Charge transfer in transition-metal-dichalcogenides (TMDs) heterostructures is a prerequisite for the formation of interlayer excitons, which hold great promise for optoelectronics and valleytronics. Charge accumulation accompanied by a charge-transfer process can introduce considerable effect on interlayer exciton-based applications; nevertheless, this aspect has been rarely studied up to date. This work demonstrates how the charge accumulation affects the light emission of interlayer excitons in van der Waals heterobilayers (HBs) consisting of monolayer WSe2 and WS2 . As excitation power increases, the photoluminescence intensity of interlayer excitons increases more rapidly than that of intralayer excitons. The phenomenon can be explained by charge-accumulation effect, which not only increases the recombination probability of interlayer excitons but also saturates the charge-transfer process. This scenario is further confirmed by a careful examination of trion binding energy of WS2 , which nonlinearly increases with the increase of the excitation power before reaching a maximum of about 75 meV. These investigations provide a better understanding of interlayer excitons and trions in HBs, which may provoke further explorations of excitonic physics as well as TMDs-based devices.

Research on the Accumulation Effect of Pension Income and Payments Caused by Progressive Retirement Age Postponement Policy in China.

A retirement age postponement policy will not only increase pension income but also reduce pension payments, which will cause an accumulation effect on the size of the pension fund and relieve the intensifying pressure on pension payments. Based on the analysis of historical data in order to predict the population and pension scale in China, this research shows that the working-age population will gradually decrease, the supply of labor will decrease, and the demographic dividend will gradually disappear between 2018 and 2055 if the current retirement policy remains unrevised. According to three different retirement age postponement policy options, we establish that there are significant accumulation effects that can alleviate the pressure on pension funds. Among these policies, the postpone retirement policy option, which is based on the working period, is more conducive to a smoother policy implementation effect in the long term.

Global risk assessment of river pollution stress based on nighttime light remote sensing data.

Rivers play a crucial role in the development of human civilization, and river pollution is a significant environmental issue that accompanies with intensified human activity. However, the evaluation of river pollution at a global scale is difficult because of the limitations of long-term pollution-related datasets. As human activities are the main factor causing river pollution, nighttime light (NTL) remote sensing data can be used as an alternative indicator of the risk of river pollution stress(RPS), which is closely related to human activities and refers to the amount of pollutants within the confluence range of river reaches. In this study, we propose a river pollution pressure index (PI) to indicate risk of RPS by considering the accumulation effect of water flow. Then we calculated PI of over 0.67 million reaches global with annual total flow >100 million m3/s from 2000 to 2022, which was validated using water quality data of >2000 river sections in China. The results show that, from 2000 to 2022, the spatial variations of the risk of RPS are uneven, with a migration trend from west to east. The risk of RPS continues to increase globally, especially rapidly after 2010. Central Asia, Southeast Asia, East Asia, and eastern China are the regions with the fastest growth rates. In most developed countries, developing countries, and underdeveloped countries, the risk of RPS is high and increasing slowly, moderate and increasing rapidly, and low and increasing slowly, respectively. However, in some special cases, such as Japan, the risk of RPS continues to decrease. These spatiotemporal variations of the risk of RPS correlate with global events, such as quantitative easing of global economy after 2008, China's "Belt and Road Initiative", and COVID-19. This study demonstrates that NTL data can be applied to evaluate the global risk of RPS.

A Systematic Study on the Processing Strategy in Femtosecond Laser Scribing via a Two-Temperature Model.

Balancing quality and productivity, especially deciding on the optimal matching strategy for multiple process parameters, is challenging in ultrashort laser processing. In this paper, an economical and new processing strategy was studied based on the laser scribing case. To reveal the temperature evolution under the combination of multiple process parameters in the laser scribing process, a two-temperature model involving a moving laser source was developed. The results indicated that the peak thermal equilibrium temperature between the electron and lattice increased with the increase in the laser fluence, and the temperature evolution at the initial position, influenced by subsequent pulses, was strongly associated with the overlap ratio. The thermal ablation effect was strongly enhanced with the increase in laser fluence. The groove morphology was controllable by selecting the overlap ratio at the same laser fluence. The removal volume per joule (i.e., energy utilization efficiency) and the removal volume per second (i.e., ablation efficiency) were introduced to analyze the ablation characteristics influenced by multiple process parameters. The law derived from statistical analysis is as follows; at the same laser fluence with the same overlap ratio, the energy utilization efficiency is insensitive to changes in the repetition rate, and the ablation efficiency increases as the repetition rate increases. As a result, a decision-making strategy for balancing quality and productivity was created.

Effects of climate change and human activities on vegetation coverage change in northern China considering extreme climate and time-lag and -accumulation effects.

Quantifying the contributions of climate change (CC) and human activities (HA) to vegetation change is crucial for making a sustainable vegetation restoration scheme. However, the effects of extreme climate and time-lag and -accumulation effects on vegetation are often ignored, thus underestimating the impact of CC on vegetation change. In this study, the spatiotemporal variation of fractional vegetation cover (FVC) from 2000 to 2019 in northern China (NC) as well as the time-lag and -accumulation effects of 15 monthly climatic indices, including extreme indices, on the FVC, were analyzed. Subsequently, a modified residual analysis considering the influence of extreme climate and time-lag and -accumulation effects was proposed and used to attribute the change in the FVC contributed by CC and HA. Given the multicollinearity of climatic variables, partial least squares regression was used to construct the multiple linear regression between climatic indices and the FVC. The results show that: (1) the annual FVC significantly increased at a rate of 0.0268/10a from 2000 to 2019 in all vegetated areas of NC. Spatially, the annual FVC increased in most vegetated areas (∼81.6 %) of NC, and the increase was significant in ∼54.6 % of the areas; (2) except for the temperature duration (DTR), climatic indices had no significant time-lag effects but significant time-accumulation effects on the FVC change. The DTR had both significant time-lag and -accumulation effects on the FVC change. Except for potential evapotranspiration and DTR, the main temporal effects of climatic indices on the FVC were a 0-month lag and 1-2-month accumulation; and (3) the contributions of CC and HA to FVC change were 0.0081/10a and 0.0187/10a in NC, respectively, accounting for 30.2 % and 69.8 %, respectively. HA dominated the increase in the FVC in most provinces of NC, except for the Qinghai and Neimenggu provinces.

Spatial heterogeneity of particulate organic matter for the sorption of ciprofloxacin at the microstructure scale.

Particulate organic matter (POM) is a major antibiotic sorbent of the active soil organic carbon pool. Until now, the spatial heterogeneity of POM for ciprofloxacin (CFC) sorption at the microstructure scale has not been quantified. To our knowledge, this is the first study that combines a batch sorption experiment, NanoSIMS, and a 13C isotopic tracer to expound the distribution characteristics of CFC and the dominant sorption components of POM. Four POMs separated from soils (wetland, oil waste field, and farmlands) were utilized to study the sorption mechanisms using batch experiments. POM separated from the wetland was utilized for further study at the microstructure scale. The results revealed that the POM had a great CFC sorption capacity ranging from 65.20 mg g-1 to 77.51 mg g-1. Both the kinetics and NanoSIMS results showed that the sorption mechanisms included surface distribution and intra-particle diffusion. The microstructural distribution characteristics exhibited a marginal accumulation tendency and a surface accumulation effect. A combination of the NanoSIMS with the pH and salinity results explained that CFC adsorption was dominated by the organic components of POM. Overall, the present study demonstrates that the characteristics and organic components of the POM played a decisive role in the CFC-POM interactions. This study provides the first evidence of the vector potential of CFC rereleased into the environment during the POM turnover process.

Evaluation of the Key Advantages between Two Modalities of Boronophenylalanine Administration for Clinical Boron Neutron Capture Therapy Using an Animal Model.

In clinical boron neutron capture therapy (BNCT), boronophenylalanine (BPA) administrations through one-step infusion (OSI) and two-step infusion (TSI) are the most widely used. This study compared the advantages of OSI and TSI using a human oral squamous cell carcinoma-bearing animal model. OSI was administered at a high-dose rate of 20 mg/kg/min for 20 min (total dose: 400 mg/kg) as the first step infusion. TSI was a prolonged infusion at a low-dose rate of 1.67 mg/kg/min for 15, 30, 45, and 60 min (total dose: 25, 50, 75, and 100 mg/kg) following the first step infusion. The sigmoid Emax model was used to evaluate the boron accumulation effect in the tumor. The advantages of TSI were observed to be greater than those of OSI. The observed advantages of TSI were as follows: a stable level of boron concentration in blood; tumor to blood boron ratio (T/B); tumor to muscle boron ratio (T/M); and skin to blood boron ratio (S/B). The boron accumulation effect in tumors increased to 68.98%. Thus, effective boron concentration in these tumor cells was achieved to enhance the lethal damage in BNCT treatment. Boron concentration in the blood was equal to that in the skin. Therefore, the equivalent dose was accurately estimated for the skin.

Dielectric Surface Flashover under Long-Term Repetitive Microsecond Pulses in Compressed Gas Environment.

As a key component of a high-power microwave (HPM) system, a multi-gap gas switch (MGS) has recently developed insulation failure due to surface flashover. Although design criteria for surface insulation have been put forward, it is still not clear how the insulation in this case deteriorated under long-term repetitive microsecond pulses (RMPs). In this paper, flashover experiments under RMPs were carried out on various dielectric surfaces between parallel-plane electrodes in SF6 and air atmospheres, respectively. Based on tests of the surface insulation lifetime (SIL), an empirical formula for SIL prediction is proposed with variations of insulator work coefficient λ, which is a more suitable parameter to characterize SIL under RMPs. Due of the accumulation effect, the relationship between E/p and ptdelay varies with the pulse repetitive frequency (PRF) and SIL recovery capability decreases with an increase in PRF and surface deterioration is exacerbated during successive flashovers. It is concluded that the flashover path plays a crucial role in surface insulation performance under RMPs due to the photoemission induced by ultraviolet (UV) radiation, signifying the necessity of reducing surface paths in future designs as well as the improvement of surface insulation.

The accumulation of rare-earth yttrium ions by Penicillium sp. ZD28.

To obtained fungal resources with excellent tolerance and accumulation capacity to rare earth yttrium ions (Y3+), rare earth ore samples were collected and used for microbial screening. A fungus hyper-resistant to Y3+ was obtained and the effects of the fungus in three physiological states (growth process, mycelial pellets with physiological activity and the fungus powder after being ground) on the Y3+ accumulation were investigated. The Y3+ resistant fungus was identified as Penicillium sp. ZD28, and its mycelium pellets (about 1 mm in diameter) showed poor ability to accumulate Y3+ with an adsorption capacity of less than 81 µmol/g. However, the fungus was able to remove 99% of Y3+ during the growth process, at an initial concentration of less than 600 µM. Bioaccumulation of Y was observed on the cell surface of the ZD28 strain by elemental mapping using scanning electron microscopy-energy dispersive X-ray spectroscopy. The adsorbent (the dry fungal powder) had a remarkable adsorption property for Y3+ that was greater than 455 µmol/g in conditions of 465 µM < [Y3+] < 6382 µM. Penicillium sp. ZD28 has major potential applications in the accumulation of yttrium group rare earth ions. This research has formed a theoretical foundation for the application of this biological method to extract rare earth ions in the mining and smelting of yttrium group rare earth elements.

Surface Characteristics of Polymers with Different Absorbance after UV Picosecond Pulsed Laser Processing Using Various Repetition Rates.

We experimented with two polymer materials with different ultraviolet (UV) wavelength absorption characteristics, which are commonly used in flexible devices, by applying an ultrashort-pulsed laser of a 355-nm UV wavelength for 10 ps. The laser parameters studied were pulse repetition rate, laser irradiation method, and laser power condition. Previous studies using polyethylene terephthalate (PET), which does not exhibit linear absorption at a UV wavelength, have focused on processing trends resulting in minimal collateral damage around the laser-induced ablation. However, our results showed a trend of accumulating such damage irrespective of the laser parameters. Meanwhile, polyimide (PI) exhibited a completely different behavior depending on the laser parameters. At low pulse repetition rates, minimal collateral damage was observed, whereas at high repetition rates, the morphology varied considerably. The electrical characteristics of the laser-processed materials were found to be correlated with the variations in morphology. In the case of PI, such variations in electrical resistance and morphology indicated that the material was carbonized. The findings of this study are expected to provide a useful reference when selecting parameters for the laser processing of similar polymer materials.

Specific Core-Satellite Nanocarriers for Enhanced Intracellular ROS Generation and Synergistic Photodynamic Therapy.

The deficiency of reactive oxygen species (ROS) is the main reason for the current poor efficiency of tumor photodynamic therapy (PDT). To solve this problem, a simple light-triggered core-satellite nanoplatform (UPSD@Au) has been developed by loading Au nanoparticles on the surface of mesoporous silica-coated upconversion nanoparticles. Small molecules DC50 (C17H14BrF2N3OS) and photosensitizer (silicon phthalocyanine dihydroxide, SPCD) were loaded into the silica shell to improve ROS production. Meanwhile, PDT can be triggered through facile near-infrared laser irradiation given the occurrence of a moderate photothermal transfer process between upconversion nanoparticles and Au. The reasonable increment in temperature induced by Au resulted in the timely release of DC50. The inhibition of copper transfer by DC50 results in reduced ROS scavenging and thus improves light-triggered ROS accumulation. Notably, the expression levels of the human copper-trafficking proteins Atox1 and CCS in cancerous cells exceed those in normal cells, and thus enhanced ROS accumulation effect was achieved in cancerous cells. In vitro and in vivo results demonstrate that the synergism between DC50 and SPCD coloaded in the UPSD@Au nanoplatform increases the efficiency of PDT. The UPSD@Au platform represents an efficient codelivery method for hydrophobic small molecules and improves sensitization to specific cancer therapy.

Dendrites in Zn-Based Batteries.

Aqueous Zn batteries that provide a synergistic integration of absolute safety and high energy density have been considered as highly promising energy-storage systems for powering electronics. Despite the rapid progress made in developing high-performance cathodes and electrolytes, the underestimated but non-negligible dendrites of Zn anode have been observed to shorten battery lifespan. Herein, this dendrite issue in Zn anodes, with regard to fundamentals, protection strategies, characterization techniques, and theoretical simulations, is systematically discussed. An overall comparison between the Zn dendrite and its Li and Al counterparts, to highlight their differences in both origin and topology, is given. Subsequently, in-depth clarifications of the specific influence factors of Zn dendrites, including the accumulation effect and the cathode loading mass (a distinct factor for laboratory studies and practical applications) are presented. Recent advances in Zn dendrite protection are then comprehensively summarized and categorized to generate an overview of respective superiorities and limitations of various strategies. Accordingly, theoretical computations and advanced characterization approaches are introduced as mechanism guidelines and measurement criteria for dendrite suppression, respectively. The concluding section emphasizes future challenges in addressing the Zn dendrite issue and potential approaches to further promoting the lifespan of Zn batteries.

Intensification of hydrological drought due to human activity in the middle reaches of the Yangtze River, China.

Hydrological extremes are changing under the impacts of environmental change, i.e., climate variation and human activity, which can substantially influence ecosystems and the living environment of humans in affected region. This study investigates the impacts of environmental change on hydrological drought in the middle reaches of the Yangtze River in China based on hydrological modelling. Change points for streamflow into two major lakes and a reservoir in the study area were detected in the late 1980s using the Mann-Kendall test. Streamflow simulation by a water balance model was performed, and the resulting Kling-Gupta efficiency value was >0.90. Hydrological drought events were identified based on the simulated streamflow under different scenarios. The results show that the hydrological drought occurrence was increased by precipitation, whereas the drought peak value was increased by potential evapotranspiration. The impacts of precipitation and potential evapotranspiration on drought severity and duration varied in the study area. However, hydrological drought was intensified by the influence of human activity, which increased the severity, duration and peak value of droughts. The dominant factor for hydrological drought severity is precipitation, followed by potential evapotranspiration and human activity. The impacts of climate variation and human activity on drought severity are larger than on drought duration. In addition, environmental change is shown to have an "accumulation effect" on hydrological drought, demonstrating that the indirect impacts of environmental change on hydrological drought are much larger than the direct impacts on streamflow. This study improves our understanding of the responses of hydrological extremes to environmental change, which is useful for the management of water resources and the prediction of hydrological disasters.

Effect of Microwave Electromagnetic Fields on Activity of Energy Metabolism Cytochrome Oxidase in Cerebral Cortical Neurons of Postnatal Rats / 环境与健康杂志

Objective To investigate the effect of low intensity microwave electromagnetic fields (EMF) on energy metabolism of cerebral cortical neurons of postnatal rats. Methods The cultured neurons were exposed to low intensity 900 MHz continuous microwave EMF (SAR=0.38-3.22 mW/g) 2 hours a day for 4 to 6 consecutive days. The activity of cytochrome oxidase(CCO) was taken as the index for energy metabolism level. Results The results of cytochemistry showed that compared to the sham-exposed, a significant decrease of cytochrome oxidase activity in exposed neurons(0.38-3.22 mW/g P