A large-strain and ultrahigh energy density dielectric elastomer for fast moving soft robot.

Dielectric elastomer actuators (DEAs) with large actuation strain and high energy density are highly desirable for actuating soft robots. However, DEAs usually require high driving electric fields (>100 MV m-1) to achieve high performances due to the low dielectric constant and high stiffness of dielectric elastomers (DEs). Here, we introduce polar fluorinated groups and nanodomains aggregated by long alkyl side chains into DE design, simultaneously endowing DE with a high dielectric constant and desirable modulus. Our DE exhibits a maximum area strain of 253% at a low driving electric field of 46 MV m-1. Notably, it achieves an ultrahigh specific energy of 225 J kg-1 at only|| ||40|| MV m-1, around 6 times higher than natural muscle and twice higher than the state-of-the-art DE. Using our DE, soft robots reach an ultrafast running speed of 20.6 BL s-1, 60 times higher than that of commercial VHB 4910, representing the fastest DEA-driven soft robots ever reported.

A hyperelastic hydrogel with an ultralarge reversible biaxial strain.

Hyperelastic materials exhibit a nonlinear elastic response to large strains, whereas hydrogels typically possess a low elastic range due to the nonuniform cross-linking and limited chain segments among cross-links. We developed a hyperelastic hydrogel that possesses a broader elastic range by introducing a reversible pearl-necklace structure, in which beads are connected by strings. The subnanometric beads can efficiently unfold and refold under cyclic mechanical strains; thus, the hydrogel can rapidly recover after being stretched to an areal strain of more than 10,000%. Additionally, the hydrogel can quickly heal from minor mechanical damages such as needle punctures and cuts. These advancements make our ionic hydrogels ideal for multifunctional pneumatic gripper materials; they simultaneously offer an ultralarge gripping range, self-sensing capabilities, and fast healing abilities.

Clinical Characteristics and Molecular Genetic Analysis of a Pedigree with Glanzmann's Thrombasthenia.

Objective: The objective of this study was to investigate the clinical phenotype and genetic etiology of Glanzmann's thrombasthenia in a consanguineous pedigree. Methods: Clinical data and ancillary test results were collected from pedigrees with Glanzmann's thrombasthenia. High-throughput sequencing was used to detect variants in the proband. Candidate variants were verified by Sanger sequencing. Results: Two patients in the pedigree were homozygous for the c.2248C>T (p. Arg750Ter) variant of the ITGB3 gene. The parents and maternal grandmother, who didn't have any recurrent haemorrhage, were found to carry a heterozygous c.2248C>T variant of the ITGB3 gene, which was absent in the aunt and paternal grandmother. Conclusion: The homozygous variant c.2248C>T (p. Arg750Ter) in the ITGB3 gene underlies the disease in this pedigree. This diagnosis will facilitate genetic counselling in this pedigree for better patient management and life guidance.

[Study on the Mechanism of Multi-Drug Resistance of Agaricus Blazei Extract FA-2-b-ß Mediated Wnt Signaling Pathway to Reverse Acute T Lymphoblastic Leukemia].

OBJECTIVE: To investigate the mechanism of drug reversing resistance of Agaricus blazei extract FA-2-b-ß on T cell acute lymphoblastic leukemia (T-ALL) cell lines. METHODS: Cell proliferation was detected by CCK-8 assay; the apoptosis, cell cycle mitochondrial membrane potential, and intracellular rhodamine accumulation were detected by flow cytometry, and apoptosis-related gene and protein expression were detected by qPCR and Western blot; the membrane surface protein MDR1 was observed by immunofluorescence microscopy. RESULTS: Different concentrations of FA-2-b-ß significantly inhibited proliferation and induced apoptosis of CCRF-CEM and CEM/C1 (P<0.05), and CCRF-CEM cell cycle were arrested at S phase, and CEM/C1 cells were arrested at G0/G1 phase. Western blot and qPCR results show that FA-2-b-ß inhibited ABCB1、ABCG2、CTNNB、MYC and BCL-2 expression, but upregulated Bax expression. In addition, FA-2-b-ß reversed the resistance characteristics of CEM/C1 drug-resistance cells, which decreased mitochondrial membrane potential, and significantly increased the intracellular rhodamine accumulation, and weakening of the expression of the membrane surface protein MDR1. With the Wnt/ß-catenin inhibitor (ICG001), the process was further intensified. CONCLUSION: Agaricus Blazei Extract FA-2-b-ß inhibits cell proliferation, promotes apoptosis, regulates the cell cycle, reduces mitochondrial energy supply, and down-regulate MDR1 expression to reverse the resistance of CEM/C1, which all suggest it is through regulating the Wnt signaling pathway in T-ALL.

Synthesis, characterization and biological activity of novel copper complexes containing a ß-carboline derivative and amino acids.

Copper complexes have long been considered as a promising class of anticancer or antibacterial therapeutics. In this paper, two novel copper(II) complexes containing a ß-carboline derivative and amino acids, namely [Cu(1-Im-ßc)(L-Val)]ClO4·0.5H2O (Cu1) and [Cu(1-Im-ßc)(L-Phe)]ClO4·0.5H2O (Cu2), where 1-Im-ßc = 1-(2-imidazolyl)-ß-carboline, L-Val = L-valine, and L-Phe = L-phenylalanine, were designed and synthesized. The complexes were characterized by elemental analysis, infrared spectroscopy, molar conductivity measurements, and mass spectrometry to determine their spatial structures and compositions. Both complexes bind to DNA by insertion. The complexes also show a good affinity for human serum albumin (HSA). In addition, the antitumor activity of the two complexes against lung cancer cells (A549), cervical cancer cells (HeLa), and breast cancer cells (MBA-MD-231) is significantly superior to that of the traditional antitumor drug, cisplatin. Finally, the anticancer mechanism results show that the complexes can induce apoptosis in HeLa cells, which is associated with mitochondrial damage, oxidative stress caused by reactive oxygen species (ROS) production, and activation of the caspase protein family. This study demonstrates that the introduction of aromatic heterocyclic alkaloid ligands with a broad spectrum of biological activities and water-soluble amino acid ligands into copper complexes can regulate their amphiphilic properties and biological activity, so as to obtain highly efficient copper-based therapeutics.

A Highly Robust Amphibious Soft Robot with Imperceptibility Based on a Water-Stable and Self-Healing Ionic Conductor.

Dielectric elastomer actuators (DEAs) are widely exploited for actuating soft machines and granting soft robots with capability to operate in both underwater and on-land environments is important to make them adapt to more complex situations. Here, a DEA-driven, highly robust, amphibious imperceptible soft robot (AISR) based on an all-environment stable ionic conductive material is presented. A soft, self-healable, all-environment stable ionic conductor is developed by introducing cooperative ion-dipole interactions to provide underwater stability as well as efficient suppression of ion penetration. By tuning molecular structures of the material, a 50-time device lifetime increase compared with unmodified [EMI][TFSI]-based devices and excellent underwater actuating performance is achieved. With the synthesized ionic electrode, the DEA-driven soft robot exhibits amphibious functionality to traverse hydro-terrestrial regions. When encountering damage, the robot shows good resilience and can self-heal underwater and it also exhibits imperceptibility to light, sound, and heat.

Multivalent Design of Low-Entropy-Penalty Ion-Dipole Interactions for Dynamic Yet Thermostable Supramolecular Networks.

Dynamic supramolecular networks are constantly accompanied by thermal instability. The fundamental reason is most reversible noncovalent bonds quickly decay at elevated temperatures and dissociate below 100 °C. Here, in this paper, we realize a reversible ion-dipole interaction with high-temperature stability exceeding 150 °C. The resultant supramolecular network can simultaneously possess mechanical strength of 1.32 MPa (14.8 times that of pristine material), dynamic self-healing capability, and a stable working temperature of up to 200 °C. From the prolonged characteristic relaxation time of 600 s even at 100 °C, our material represents one of the most thermally stable dynamic supramolecular polymers. These remarkable performances are achieved by using a new multivalent yet low-entropy-penalty molecular design. In this way, the noncovalent bond can reach a high enthalpy while minimizing the entropy-dominated thermal dissociations.

A Recognition Method of Truck Drivers' Braking Patterns Based on FCM-LDA2vec.

Taking truck drivers' braking patterns as the research objects, this study used a large amount of truck running data. A recognition method of truck drivers' braking patterns was proposed to determine the distribution of braking patterns during the operation of trucks. First, the segmented data of braking behaviors were collected in order to extract 25 characteristic parameters. Additionally, seven main correlation factors were obtained by dimensionality reduction. The FCM clustering algorithm and CH scores were used to identify nine categories of truck drivers' braking behaviors. Then the LDA2vec model was used to identify the distribution of different braking behavior words in braking patterns, and three categories of truck drivers' braking patterns were identified. The test results showed that the accuracy of the truck drivers' braking pattern recognition model based on LDA2vec was higher than 85%, and braking patterns of drivers in the daily operation process could be mined from vehicle operation data. Furthermore, through the monitoring and pre-warning of the braking patterns and targeted training of drivers, traffic accidents could be avoided. At the same time, this paper's results can be used to protect human life and health and reduce environmental pollution caused by traffic congestion or traffic accidents.

Efficacy and safety of mycophenolate mofetil in the treatment of moderate to severe Graves' orbitopathy: a meta-analysis.

The role of mycophenolate mofetil (MMF) in the treatment of Graves' orbitopathy (GO) has attracted much attention. This study is to evaluate the benefit and safety of MMF in moderate-to-severe GO. A meta-analysis of clinical control trials comparing MMF (with or without glucocorticoid (GC)) for the treatment of GO with GC was conducted. We searched the databases, including PubMed, EMBASE, the Cochrane Library, Web of Science, Wanfang, and China National Knowledge Infrastructure (CNKI), for articles published up to 15 June 2022. The primary outcome is referred to the improvement in overall response, and secondary outcomes included the change in clinical activity score (CAS) and adverse events (AEs). Of the 289 articles initially searched, 6 studies were finally eligible for inclusion. The results showed that MMF (with or without GC) was superior to GC in the treatment of GO (OR 3.34, 95% CI 2.17-5.14; p < 0.00001). Subgroup analyses also showed that MMF monotherapy was more effective than GC (OR 4.46, 95% CI 2.52-7.87; p < 0.00001). Compared to methylprednisolone (MP) monotherapy, a combination of MP and MMF was more effective. CAS decreased even more significantly (WMD 0.29, 95% CI 0.10-0.48; p = 0.002) and fewer AEs occurred (OR 0.2, 95% CI 0.06-0.72; p = 0.01) in patients receiving MMF. The pooled data suggested that MMF treatment in GO might be promising. Compared with GC therapy, MMF is safer and more effective. However, more large-sample and high-quality studies targeting MMF use in GO patients and long-term surveillance of prognosis are urgently needed.

Stable High-Temperature Lithium-Metal Batteries Enabled by Strong Multiple Ion-Dipole Interactions.

Lithium-metal batteries (LMBs) capable of operating stably at high temperature application scenarios are highly desirable. Conventional lithium-ion batteries could only work stably under 60 °C because of the thermal instability of electrolyte at elevated temperature. Here we design and develop a thermal stable electrolyte based on stable solvation structure using multiple ion-dipole interactions. The strong coordination in solvated structure of electrolyte defines the Li deposition behaviour and the evolution of solid electrolyte interphase at high temperature, which is important to achieve high Li Coulombic efficiency and avoid Li dendritic growth. For high mass loading LiFePO4 -Li cells, the cells at 60 °C with conventional electrolyte easily run into failures, but the cells with our electrolyte at 90 °C and 100 °C could cycle more than 120 and 50 cycles respectively. This work provides new insight into electrolyte design and contributes to the development of high temperature LMBs.

Superstretchable, yet stiff, fatigue-resistant ligament-like elastomers.

Ligaments are flexible and stiff tissues around joints to support body movements, showing superior toughness and fatigue-resistance. Such a combination of mechanical properties is rarely seen in synthetic elastomers because stretchability, stiffness, toughness, and fatigue resistance are seemingly incompatible in materials design. Here we resolve this long-standing mismatch through a hierarchical crosslinking design. The obtained elastomer can endure 30,000% stretch and exhibit a Young's modulus of 18 MPa and toughness of 228 MJ m-3, outperforming all the reported synthetic elastomers. Furthermore, the fatigue threshold is as high as 2,682 J m-2, the same order of magnitude as the ligaments (~1,000 J m-2). We reveal that the dynamic double-crosslinking network composed of Li+-O interactions and PMMA nanoaggregates allows for a hierarchical energy dissipation, enabling the elastomers as artificial ligaments in soft robotics.

Short Term Real-Time Rolling Forecast of Urban River Water Levels Based on LSTM: A Case Study in Fuzhou City, China.

Water level management is an important part of urban water system management. In flood season, the river should be controlled to ensure the ecological and landscape water level. In non-flood season, the water level should be lowered to ensure smooth drainage. In urban areas, the response of the river water level to rainfall and artificial regulation is relatively rapid and strong. Therefore, building a mathematical model to forecast the short-term trend of urban river water levels can provide a scientific basis for decision makers and is of great significance for the management of urban water systems. With a focus on the high uncertainty of urban river water level prediction, a real-time rolling forecast method for the short-term water levels of urban internal rivers and external rivers was constructed, based on long short-term memory (LSTM). Fuzhou City, China was used as the research area, and the forecast performance of LSTM was analyzed. The results confirm the feasibility of LSTM in real-time rolling forecasting of water levels. The absolute errors at different times in each forecast were compared, and the various characteristics and causes of the errors in the forecast process were analyzed. The forecast performance of LSTM under different rolling intervals and different forecast periods was compared, and the recommended values are provided as a reference for the construction of local operational forecast systems.

pH-dependent biological sulfidogenic processes for metal-laden wastewater treatment: Sulfate reduction or sulfur reduction?

Both biological sulfate reduction process and sulfur reduction process are attractive technologies for metal-laden wastewater treatment. However, the acidity stress of metal-laden wastewater could affect the sulfidogenic performance and the microbial community, weaken the stability, efficiency and cost-effectiveness of the biological sulfidogenic processes (BSP). In this study, long-term lab-scale trials were conducted with a sulfate-reducing bioreactor and a sulfur-reducing bioreactor to evaluate the effects of acidity on sulfidogenic activities and the microbial community of the BSP. In the 300-day trial, the sulfate-reducing bacteria (SRB)-driven BSP was stable in terms of sulfidogenic performance and microbial community with the decline of pH, while the sulfur-reducing bacteria (S0RB)-driven BSP achieved high-rate and low-cost sulfide production under neutral conditions but unstable under acidic conditions. With the decline of pH, the sulfide production rate (SPR) of the SRB-driven BSP stably increased from 30 to 83 mg S/L-h; while it decreased from 56 to 37 mg S/L-h in the S0RB-driven BSP with high fluctuation. The results of estimation were consistent with the thermodynamical calculations, in which the sulfur reduction process showed a better performance at pH 5-7, while the sulfate reduction process might gain more energy when pH<5. The stable sulfidogenic performance and microbial community diversity of the SRB-driven BSP could be attributed to the alkalinity produced in sulfate reduction to buffer the acidic stress. In comparison, the microbial community in the S0RB-driven BSP was significantly re-shaped by acidity stress, and the predominant sulfidogenic bacterium changed from Desulfovibrio at neutral condition, to Desulfurella at pH≤5.4. The stability of the microbial community significantly affected the SPR and the operational cost. Nevertheless, the organic consumption for sulfide production of the S0RB-driven BSP was still less than the SRB-driven BSP even in acidic conditions. Collectively, the S0RB-driven BSP was recommended under neutral or mild acid conditions, while the SRB-driven BSP was more suitable under fluctuating pH conditions, especially at low pH. Overall, this study presented the long-term performance of SRB- and S0RB-driven BSP under varying pH conditions, and provided guidance to determine the suitable BSP and operational cost for different metal-laden wastewater.

Effect of selenium on thyroid autoimmunity and regulatory T cells in patients with Hashimoto's thyroiditis: A prospective randomized-controlled trial.

Selenium (Se) is an essential trace element in human. Recent studies of Se supplementation on the effect of Hashimoto's thyroiditis (HT) have been reported, but the exact benefit is unclear as well as the underlying immunologic mechanism. We aimed to evaluate the clinical effect of Se supplement in patients with HT, and explore the potential mechanism against thyroid autoimmunity. A prospective, randomized-controlled study was performed in patients with HT assigned to two groups. Se-treated group (n = 43) received selenious yeast tablet (SYT) for 6 months, whereas no treatment in control group (n = 47). The primary outcome is the change of thyroid peroxidase antibody (TPOAb) or thyroglobulin antibody (TGAb). Second, thyroid function, urinary iodine, Se, Glutathione peroxidase3 (GPx3), and Selenoprotein P1 (SePP1) levels were measured during the SYT treatment. Meanwhile, regulatory T cells (Tregs) and their subsets activated Tregs (aTregs), resting Tregs, and secreting Tregs, as well as Helios and PD-1 expression on these cells were also detected. The results showed that SYT treatment significantly decreased TPOAb, TGAb, and thyroid stimulating hormone (TSH) levels, accompanied with the increased Se, GPx3, and SePP1, compared with the control group. Subgroup analysis revealed that subclinical HT may benefit more from this treatment in the decrease of TSH levels by interaction test. Moreover, the percentage of aTregs, Helios/Tregs, and Helios/aTregs were significantly higher in the Se-treated group than control. In conclusion, Se supplementation may have a beneficial effect on thyroid autoantibodies and thyroid function by increasing the antioxidant activity and upregulating the activated Treg cells.

Exogenous enzyme amendment accelerates maturity and changes microflora succession in horse and wildlife animal manure co-composting.

Composting has been a rational method to dispose of horse or wildlife animal manures, especially in the developed cities with horse clubs and wildlife parks. However, few studies have focused on the mechanism and improvement methods for composting the horse or wildlife animal manures. In this study, we investigated the effect of exogenous compound enzymes on thermophilic composting, which could potentially support the management of horse and wildlife animal manures. With the presence of exogenous enzymes, the duration of high temperature (> 60 °C) was significantly prolonged (p < 0.05), and the germination index was significantly improved (p < 0.05). More-efficient improvement of composting maturity was associated with the addition of that exogenous enzyme that might influence microflora succession and the interaction among microorganic communities, especially fungal, during the composting process. Furthermore, redundancy and canonical correspondence analyses indicated that the C/N ratio, temperature, and germination index were significant variations to influence bacterial communities (p < 0.05). The dominant Flavobacterium, Thermopolyspora, Thermomonospora, and Chaetomium and Saccobolus could play an essential role in carbohydrate and phytotoxin degradation, while Thermobispora and norank_f_Limnochordaceae could lead to temperature rising.

Distribution of Nitrate Content in Groundwater and Evaluation of Potential Health Risks: A Case Study of Rural Areas in Northern China.

Nitrate pollution is considered to be one of the most common environmental problems in groundwater, especially in areas affected by human mining, such as the arid region of northern China. However, the human health risk assessment of nitrate pollution in this area has not yet been carried out. In this study, groundwater samples were taken in the Selian mining area in Inner Mongolia to conduct a full analysis of water quality. On this basis, the groundwater quality, the distribution range of nitrate pollution, and human health risks were evaluated. The results show that the groundwater in the Selian mining area is neutral to alkaline, with high salinity and hardness. The concentration of nitrate ions in groundwater generally exceeds the standard, and the maximum exceeds 5.48 times the value specified in the Chinese national standard, indicating that groundwater nitrate pollution needs to be controlled urgently. Groundwater is polluted by large amounts of nitrogen fertilizer used by humans in agricultural activities. At the same time, mining activities have accelerated the severity and spread of pollution. Groundwater is not recommended for direct human life and irrigation use in the study area unless purification measures are taken. Nitrate pollution is more harmful to children through groundwater, about 1.54 times that of adults. Excess nitrate is transported into the body through drinking groundwater, so proper drinking water control will reduce the health risks of nitrate, such as centralized water supply. This study will provide a scientific basis for the rational use of groundwater and nitrate pollution control in the area.

[Microbial Community Succession in Industrial Composting with Livestock Manure and Peach Branches and Relations with Environmental Factors].

This study sets out to understand the evolution of the microbial community structure in industrial composting with livestock manure and peach branches. Pig manure, peach branches, and decomposed organic fertilizer were used as materials for composting. Changes in physical and chemical indicators and the evolution in the structure of the compost microbial community, determined by high-throughput sequencing, were analyzed. The results of physical and chemical parameters show that the pile reached the high-temperature stage on day 2, and the thermophilic period lasted for 30 days. The changes in total carbon were volatile, and there was an overall decline in the amount of TOC in the whole process of composting; The final content of TN was 20.58 g·kg-1, which was 5.90% lower compared to the initial compost. Alpha analysis indicated that a different microbial community diversity existed at different times during aerobic composting periods. At the bacterial phyla level, Firmicutes and Actinobacteria were the dominant phyla, and the proportion of relative abundance were 79.31%-95.09% and 2.98%-19.70%, respectively, in the entire compost. The relative abundance of Firmicutes and Actinobacteria were 87.36% and 9.66%, respectively, and their respective relative abundances were 79.38% and 19.70% at the end of composting. At the bacterial genus level, the dominant group changed from Clostridium_sensu_stricto_1, Terrisporobacter, and Bacillus to norank_f_Bacillaceae, Bacillus, Oceanbacillus, and Pseudogracilibacillus; Regarding the fungus phyla, the Ascomycota was the dominant phylum. For the fungus genus, the relative abundance of norank_c_Sordariomycetes gradually increased during composting, and finally was predominant group. The redundancy analysis (RDA) showed that the correlation rank between environmental factors and microbial community structure was:pH > NH4+-N > T > TOC > TN, where pH had the greatest impact on the microbial community composition. norank_c_Sordariomycetes, norank_o_Sordariales, and norank_c_Agaricomycetes may be related to the volatilization of ammonium nitrogen.

Alterations to groundwater chemistry due to modern water transfer for irrigation over decades.

After a long-term surface irrigation in the southern edge of the Chinese Loess Plateau, the local groundwater is diluted to some extent, which differs from most of the other surface irrigation systems. Identifying the origin of groundwater salinity and determining the implications of irrigation can provide insights into the sustainable development of irrigation systems. In this study, a comprehensive investigation of groundwater, river water, canal water, and irrigation system was conducted. Our results suggest that the irrigation activities produce significant influence on the hydrochemistry of both river and groundwater. In the north-eastern part of the study area, hydrochemistry types are mainly HCO3-Na and HCO3∙SO4-Na types which is recharged by the river replenished by water transfer for irrigation. In the south-western part, groundwater is mainly HCO3-Na·Mg type which largely directly receives canal water recharge. The correlation between the irrigation water volume and the salinity variation confirms that mixing with fresh irrigation water which was derived from the reservoirs and the canals, during the irrigation period, dilutes the local groundwater. The natural hydrogeochemical processes of the loess aquifer suggest that the water-rock interactions and cation exchange process supply the excessive Na+ and other solutes to the groundwater, resulting HCO3-Na type water with high salinity. Additionally, the slow Groundwater flow and poor hydrologic cycle between the groundwater and the scarce rainfall promote natural salts accumulation. The δ18O and δD values indicate that modern rainfall may only account for small part of recharge to groundwater. In contrast, the irrigation water, as well as the canal and the reservoir seepage, contribute to a large proportion of groundwater recharge. The finding is beneficial for the policy-makers for the future water management schemes, in large surface irrigation systems, in order to achieve sustainable development goal.

Hydrogeochemical Characterization and Irrigation Quality Assessment of Shallow Groundwater in the Central-Western Guanzhong Basin, China.

Groundwater is the major water resource for the agricultural development of the Guanzhong Basin, China. In this study, a total of 97 groundwater samples (51 from the North Bank of the Wei River (NBWR) and 46 from the South Bank of the Wei River (SBWR)) were collected from the central-western Guanzhong Basin. The aim of this study was to investigate the hydrogeochemical characteristics of the basin and to determine the suitability of shallow groundwater for irrigation. The groundwater of the entire study area is alkaline. The groundwater of the SBWR is fresh water, and the NBWR groundwater is either freshwater or brackish water. The average concentration of ions (except for Ca2+) in SBWR samples is lower than in NBWR samples. HCO3- is dominant in the groundwater of the study area. Ca2+ is dominant in the SBWR while Na+ is dominant in the NBWR. The SBWR groundwater is mainly of the HCO3-Ca·Mg type, and has undergone the main hydrogeochemical processes of rock weathering-leaching. The hydrochemical facies of the majority of the NBWR groundwater samples are the HCO3-Na type with several minor hydrochemical facies of the HCO3-Ca·Mg, SO4·Cl-Na, and SO4·Cl-Ca·Mg types. Its chemistry is mainly controlled by rock weathering, cation exchange, and evaporation. Salinity hazard, sodium percentage, sodium adsorption ratio, residual sodium carbonate, magnesium hazard, permeability index, Kelley's ratio, potential salinity, synthetic harmful coefficient, and irrigation coefficient were assessed to evaluate the irrigation quality of groundwater. The results of the comprehensive consideration of these indicators indicate that the percentage of NBWR water samples suitable for irrigation purposes ranges between 15.7% and 100% at an average level of 56.7%. Of the SBWR water samples suitable for irrigation, the percentage ranges from 78.3% to 100% with an average of 91.8%. Land irrigated with such water will not be exposed to any alkali hazard, but will suffer from a salinity hazard, which is more severe in the NBWR. Thus, most of the water in the NBWR can be used for soils with good drainage conditions which control salinity.

Fluoride Occurrence and Human Health Risk in Drinking Water Wells from Southern Edge of Chinese Loess Plateau.

Fluoride hydrogeochemistry and associated human health risks implications are investigated in several aquifers along the southern edge of the Chinese Loess Plateau. Locally, 64% shallow groundwater samples in loess aquifer exceed the fluoride limit (1.5 mg/L) with the maximum of 3.8 mg/L. Presently, the shallow groundwater is the main source of private wells for domestic use, and this is clearly a potential risk for human health. Hydrogeochemistry and stable isotopes are used to elucidate the diversity of occurrence mechanisms. Enrichment of fluoride in groundwater is largely controlled by the F-containing minerals dissolution. Furthermore, alkaline condition and calcium-removing processes promote water-rock interactions. Stable isotopes of hydrogen and oxygen (δD and δ18O) in study area waters demonstrate that groundwater in loess aquifer is old, which means groundwater remains in the aquifer for a long time. Long residence time induces sufficient water-rock interactions, which play significant roles in the resolution of fluoride minerals. Samples from the shallow loess aquifer show elevated fluoride levels, which may pose human health risk for both adults (60%) and children (94%) via oral intake. To ensure drinking water safety, management measures such as popularizing fluoride-removing techniques and optimizing water supply strategies need to be implemented.