Access to safe drinking water is one of the fundamental human rights and an important part of healthy living. This study considered various land use methods, used geostatistical analysis, and ...triangular random model to explore nitrogen pollution and estimate its potential risk to human health for local populations in Songnen Plain of Northeast China and recognize parameter uncertainties. Nitrate concentrations in groundwater ranged from 0.01 to 523.45 mg/L, more than 72.35% of the samples exceeded Grade III threshold (20 mg/L of N) as per China's standard, and nitrate nitrogen content is greater than 20 mg/L accounted for around 60% of the research area, mainly distributed in the eastern and central high plain area. The nitrate-nitrogen content of groundwater in the town land was significantly higher than that of agricultural land, and the ammonia nitrogen content was conversely. The townland's risk value was two times that of agricultural land, considering different land use methods would avoid overestimating or underestimating regional risk value. Non-carcinogenic risks (HI) of two land use were above the safety level (i.e., HI > 1), suggesting that groundwater nitrate would have significant health effects on the age groups, and further threaten children. There was a wide range of fluctuations in the uncertainty of nitrogen concentration and model evaluation parameters; triangular random model was more sensitive to data changes, which could reduce the uncertainty. The contribution rate of nitrate-nitrogen concentration to risk was above 90%, which explained the need for random sampling to improve the evaluation results reliability. The findings in this paper will provide new insight for solving uncertainties in water safety management.
•Nitrate-nitrogen content in townland was higher than that of agricultural land.•The townland's risk value was two times that of agricultural land.•Triangular stochastic models would reduce the risk uncertainty.•Nitrate-nitrogen concentration was the most sensitive to risk values.
Low-alloy wear-resistant steel often requires the addition of trace alloy elements to enhance its performance while also considering the cost-effectiveness of production. In order to comparatively ...analyze the strengthening mechanisms of Mo and Cr elements and further explore economically feasible production processes, we designed two types of low-alloy wear-resistant steels, based on C-Mn series wear-resistant steels, with individually added Mo and Cr elements, comparing and investigating the roles of the alloying elements Mo and Cr in low-alloy wear-resistant steels. Utilizing JMatPro software to calculate Continuous Cooling Transformation (CCT) curves, conducting thermal simulation quenching experiments using a Gleeble-3800 thermal simulator, and employing equipment such as a metallographic microscope, transmission electron microscope, and tensile testing machine, this study comparatively investigated the influence of Mo and Cr on the microstructural transformation and mechanical properties of low-alloy wear-resistant steels under different cooling rates. The results indicate that the addition of the Mo element in low-alloy wear-resistant steel can effectively suppress the transformation of ferrite and pearlite, reduce the martensitic transformation temperature, and lower the critical cooling rate for complete martensitic transformation, thereby promoting martensitic transformation. Adding Cr elements can reduce the austenite transformation zone, decrease the rate of austenite formation, and promote the occurrence of low-temperature phase transformation. Additionally, Mo has a better effect on improving the toughness of low-temperature impact, and Cr has a more significant improvement in strength and hardness. The critical cooling rates of C-Mn-Mo steel and C-Mn-Cr steel for complete martensitic transition are 13 °C/s and 24 °C/s, respectively. With the increase in the cooling rate, the martensitic tissues of the two experimental steels gradually refined, and the characteristics of the slats gradually appeared. In comparison, the C-Mn-Mo steel displays a higher dislocation density, accompanied by dislocation entanglement phenomena, and contains a small amount of residual austenite, while granular ε-carbides are clearly precipitated in the C-Mn-Cr steel. The C-Mn-Mo steel achieves its best performance at a cooling rate of 25 °C/s, whereas the C-Mn-Cr steel only needs to increase the cooling rate to 35 °C/s to attain a similar comprehensive performance to the C-Mn-Mo steel.
Cancer has long been viewed as a disease of normal development gone awry. Cancer stem-like cells (CSCs), also termed as tumor-initiating cells (TICs), are increasingly recognized as a critical tumor ...cell population that drives not only tumorigenesis but also cancer progression, treatment resistance and metastatic relapse. The let-7 family of microRNAs (miRNAs), first identified in C. elegans but functionally conserved from worms to human, constitutes an important class of regulators for diverse cellular functions ranging from cell proliferation, differentiation and pluripotency to cancer development and progression. Here, we review the current state of knowledge regarding the roles of let-7 miRNAs in regulating cancer stemness. We outline several key RNA-binding proteins, long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs) involved in the regulation of let-7 biogenesis, maturation and function. We then highlight key gene targets and signaling pathways that are regulated or mutually regulated by the let-7 family of miRNAs to modulate CSC characteristics in various types of cancer. We also summarize the existing evidence indicating distinct metabolic pathways regulated by the let-7 miRNAs to impact CSC self-renewal, differentiation and treatment resistance. Lastly, we review current preclinical studies and discuss the clinical implications for developing let-7-based replacement strategies as potential cancer therapeutics that can be delivered through different platforms to target CSCs and reduce/overcome treatment resistance when applied alone or in combination with current chemo/radiation or molecularly targeted therapies. By specifically targeting CSCs, these strategies have the potential to significantly improve the efficacy of cancer therapies.
•Tidal wetlands along the mainland coast of China are taken as a case in this study.•Time-series water percent maps are used to detect changes in tidal wetland states.•Between 1999 and 2019, about ...53,000 ha tidal wetlands were converted into open water.•12% of the current tidal wetlands are significantly transitioning towards open water.•A four-quadrant model is used to guide tidal wetlands management in China.
The conversion of tidal wetlands to open water has become a major concern for coastal managers worldwide. Collecting spatial information regarding the lost tidal wetlands resulting from open-water conversion and the degraded tidal wetlands that are exhibiting a significant transition towards open water is the prerequisite for employing conservation and restoration efforts. Previous studies have focused on the former information while often neglecting the latter. This will hamper coastal managers to make comprehensive decisions. In this study, tidal wetlands along the mainland coast of China are taken as a case. Using a linear regression model, we first verify that the time series water percent maps can capture the changes in inundation of tidal wetlands at the local scale, and then employ this dataset and method to identify the portions within the current tidal wetlands (2020) that are exhibiting a significant transition toward open-water at the national scale. Furthermore, we optimize the spatial information of the lost tidal wetlands resulting from open-water conversion on the mainland coast of China from 1999 to 2019 based on a global intertidal change database. The results suggest that a total of 5.3 × 104 ha of tidal wetlands were converted into open-water on the mainland coast of China between 1999 and 2019, with over 57% of this occurring in Jiangsu Province and Shandong Province. Nearly 12% of China’s current tidal wetlands, equivalent to 10.1 × 104 ha, are undergoing a significant transition toward open water. The area proportion of these degraded wetlands in the provinces north of Shanghai is generally higher than that in the provinces south of Shanghai, except for Hainan Province. The four-quadrant model is utilized to provide conservation and restoration recommendations for different coastal segments based on the comprehensive spatial information on the open-water conversion of tidal wetlands. The datasets and methods used in this study provide novel insights for determining open-water conversion of tidal wetlands. Our findings have the potential to assist coastal managers in optimizing the spatial patterns of the national restoration projects along the mainland coast of China.
Changbai Mountain area is an important mineral water storage and development area in China. The hydrochemical composition of mineral water is the decisive factor for mineral–water quality. Based on ...the hydrochemical data of 74 mineral water samples collected from 2018 to 2020, the characteristics and formation mechanism of the hydrochemical components of the mineral water were analyzed. The results show that the formation of single-type mineral springs (metasilicate mineral water) is controlled by rock weathering; compound mineral springs (metasilicate mineral water with high CO
2
content) are the product of CO
2
-rich, weakly acidic, confined hot groundwater with high salinity, which are mixed with shallow groundwater as rising along the fracture. The volcanic geological process greatly influences the formation of the hydrochemical components of mineral springs on the North slope of Changbai Mountain. The mineral springs on the Longgang Mountain are greatly affected by human activities. The results of cluster analysis only consider that hydrochemical components are consistent with the classification of the areas which concentrated distributions of mineral as determined by hydrogeological and geomorphological studies. The results of this study are useful for understanding the distribution, hydrochemical characteristics, and formation mechanism of mineral springs in the Changbai Mountain area of China and provide the theoretical basis for the protection and development of mineral spring.
In this paper, a new concept of forward-pumped random Raman fiber laser (RRFL)-based liquid refractive index sensing is proposed for the first time. For liquid refractive index sensing, the flat ...fiber end immersed in the liquid can act as the point reflector for generating random fiber lasing and also as the sensing head. Due to the high sensitivity of the output power of the RRFL to the reflectivity provided by the point reflector in the ultralow reflectivity regime, the proposed RRFL is capable of achieving liquid refractive index sensing by measuring the random lasing output power. We theoretically investigate the effects of the operating pump power and fiber length on the refractive index sensitivity for the proposed RRFL. As a proof-of-concept demonstration, we experimentally realize high-sensitivity half-open short-cavity RRFL-based liquid refractive index sensing with the maximum sensitivity and the sensing resolution of–39.88W/RIU and 2.5075×10
−5
RIU, respectively. We also experimentally verify that the refractive index sensitivity can be enhanced with the shorter fiber length of the RRFL. This work extends the application of the random fiber laser as a new platform for highly-sensitive refractive index sensing in chemical, biomedical, and environmental monitoring applications, etc.
With the acceleration of the construction of sponge cities in China, porous asphalt pavement (PA) is has been widely used. High-viscosity asphalt (HVA) is the core material in building PA because it ...has good rheology properties, which can provide good raveling and rutting resistance. However, due to the open-graded structure of PA, HVA was more susceptible to rapid aging, which significantly affects the durability of PA. To investigate the thermal aging effect on the rheological properties of self-modified HVA (SHVA), five types of asphalts were aged using a rolling thin film oven (RTFO) and pressure aging vessel (PAV). Then, rheological tests were adopted, such as temperature sweep test (TS), repeated creep and recovery test (RCR), and bending beam rheometer test (BBR). The results indicate that during the aging process, the oxidation-induced hardening effect of neat asphalt and the degradation-induced softening effect of the modifier changes the rheology properties of HVA significantly. As the aging progresses, the contribution of the modifiers of HVA to anti-aging performance is greatly reduced. At high temperatures, HVA demonstrates better anti-aging performance than conventional styrene–butadiene–styrene (SBS)-modified asphalt (Guo Chuang, GC). The change of the high-temperature rheological indices of the two HVA types (SHVA and TAFPACK-super HVA (TPS)) showed a smaller activation energy index (EAI), a more considerable viscous component of binder creep stiffness (Gv), and more minor accumulated stain (racc), indicating a more significant anti-short-term and long-term aging performance, which is beneficial to the high-temperature performance of asphalts. However, the changes in low-temperature rheological properties do not align with those in high-temperature rheological properties after long-term aging. The BBR test results reveal that TPS exhibits worse low-temperature performance than GC and SHVA. During the thermal aging process, the contribution rate of the modifiers in SHVA against RTFO and PAV aging is higher than that of the modifiers in TPS, which contributes to the superior anti-aging property. Overall, SHVA demonstrates the best anti-aging performance among the five asphalts tested.
Earth–rock dams are typical soil–rock mixtures with high heterogeneity. Mastering the effect of dam heterogeneity on seismic wavefields is the premise of accurately detecting hidden risks in dams. In ...this paper, based on the soil–rock mixture characteristics of actual dams, a soil–rock mixture model that can reflect the heterogeneity of dams is established through local segmentation and reassignment of random disturbances. The influence of local area size on model heterogeneity is described. The seismic wavefield in a soil–rock mixture dam is numerically simulated through a staggered-grid finite-difference algorithm with second-order accuracy in time and sixth-order accuracy in space. Then, the effect of dam heterogeneity on effective wavefields is analyzed. The results show that the heterogeneity of the earth–rock dam can lead to scattered waves in the seismic wavefield, and the scattered waves are mainly generated by Rayleigh surface waves. In the seismic record, scattered waves with strong energy appear in the region below the surface waves. The scattered wave energy is weak and close to that in the homogeneous media in the region above the surface waves. As the rock content in the dam increases, the scattering of seismic wavefields and the energy of scattered waves weaken gradually. The scattered waves generated by the heterogeneity of the dam significantly impact the reflected longitudinal wave and converted wave but, affect the reflected shear wave less. The numerical simulation results are consistent with the acquired seismic wavefield from the field test, proving the effectiveness of the numerical simulation for the seismic wavefield propagation characteristics of the earth–rock dam.
Gut microbiome plays an indispensable role in the occurrence and progression in various diseases. The incidence of pancreatic cancer (PC) and liver metastasis (PCLM) are high, most of them are found ...in advanced stage. Therefore, it is particularly necessary to search for predictive biomarkers, which are helpful for early detection and treatment, and thus improve the survival rate and quality of life of PC patients.
We retrospectively analyzed 44 pancreatic cancer patients (P group,
= 44) and 50 healthy people (N group,
= 50) from March 21, 2021 and August 2, 2022. Among all PC patients, we divided them into liver metastasis group (LM group,
= 27) and non-liver metastasis group (non-LM group,
= 17). DNA was extracted and 16S ribosomal RNA (16S rRNA) gene sequencing was performed. SPSS was used for statistical analyses and all bioinformatics analyses were based on QIIME2,
< 0.05 were considered statistically significant.
The microbial richness and diversity of group P and LM were higher than that of group N and non-LM. LEfSe analysis found that
was a significantly different microorganism, which was further identified by random forest (RF) model, and its ability to predict PC and PCLM was verified by ROC curve.
We demonstrated significant differences in intestinal microbiome composition between PC patients and healthy people, and found that
is a potential biomarker for early prediction of PC and PCLM, which is critical for early diagnosis of diseases.
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