Combined effects of biochar and biodegradable mulch film on chromium bioavailability and the agronomic characteristics of tobacco.

Biochar (BC) and biodegradable mulch film (BMF) are both commonly used means of production in agriculture. In recent years, most studies have focused on the effects of BC or BMF on soil heavy metal pollution, while they have neglected the combined effects. In this study, a pot experiment was conducted to examine the impacts of BMF, BC, and combined BMF and BC (CMB) on the mobility of chromium (Cr) and the agronomic characteristics of flue-cured tobacco. Compared with the control, BMF, BC, and CMB significantly reduced the concentrations of diethylenetriamine pentaacetic acid (DTPA) extractable Cr in soils by 29.07-29.75%, 45.35-48.54%, and 34.21-37.92%, respectively. In comparison to the application of BMF and BC alone, co-application reduced the availability of Cr in soil via increasing the adsorption of soil Cr and soil enzyme activity, which resulted in the decrease of Cr content and bioconcentration factor and in plants. Moreover, the combined application increased the plant height, stem diameter, leaf area, total root area, root tip number, and root activity of tobacco, which leaded to increase in leaf and root biomass by 11.40-67.01% and 23.91-50.74%, respectively. Therefore, the application of CMB can reduce the heavy metal residues in tobacco leaves and improve tobacco yield and quality.

Identifications of three novel alleles of Serrate in Drosophila.

The Notch signaling pathway, an evolutionarily highly conserved pathway, participates in various essential physiological processes in organisms. Activation of Notch signaling in the canonical manner requires the combination of ligand and receptor. There are two ligands of Notch in Drosophila: Delta (Dl) and Serrate (Ser). A mutation mf157 is identified for causing nicks of fly wings in genetic analysis from a mutant library (unpublished) that was established previously. Immunofluorescent staining illustrates that mf157 represses the expression of Cut and Wingless (Wg), the targets of Notch signaling. MARCM cloning analysis reveals that mf157 functions at the same level or the upstream of ligands of Notch in signaling sending cells. Sequencing demonstrates that mf157 is a novel allele of the Ser gene. Subsequently, mf553 and mf167 are also identified as new alleles of Ser from our library. Furthermore, the complementary assays and the examination of transcripts confirm the sequencing results. Besides, the repressed phenotypes of Notch signaling were reverted by transposon excision experiments of mf157. In conclusion, we identify three fresh alleles of Ser. Our works supply additional genetic resources for further study of functions of Ser and Notch signaling regulation.

Synergistic Effects of Oligochitosan and Pyraclostrobin in Controlling Leaf Spot Disease in Pseudostellaria heterophylla.

Pseudostellaria heterophylla (or Taizishen in Chinese), a medicinal, edible, and ornamental Chinese herb, is seriously affected by leaf spot disease (LSD). Oligochitosan is a natural agricultural antibiotic that is produced via the degradation of chitosan, which is deacetylated from chitin; pyraclostrobin is a broad-spectrum and efficient strobilurin fungicide. In this work, the ability of pyraclostrobin, oligochitosan, and their formula to manage P. heterophylla leaf spot disease and their role in its resistance, leaf photosynthesis, agronomic plant traits, root growth, and root quality were studied. The results show that the joint application of oligochitosan and low-dosage pyraclostrobin could control LSD more efficiently, with control effects of 85.75-87.49% compared to high-dosage pyraclostrobin or oligochitosan alone. Concurrently, the application of this formula could more effectively improve the resistance, leaf photosynthesis, agronomic plant traits, root yield, and medicinal quality of P. heterophylla, as well as reduce the application of pyraclostrobin. This finding suggests that 30% pyraclostrobin suspension concentrate (SC) 1500-time + 5% oligosaccharin aqueous solutions (AS) 500-time diluent can be recommended for use as a feasible formula to manage LSD and reduce the application of chemical pesticides.

Tracing the substrate translocation mechanism in P-glycoprotein.

P-glycoprotein (Pgp) is a prototypical ATP-binding cassette (ABC) transporter of great biological and clinical significance.Pgp confers cancer multidrug resistance and mediates the bioavailability and pharmacokinetics of many drugs (Juliano and Ling, 1976; Ueda et al., 1986; Sharom, 2011). Decades of structural and biochemical studies have provided insights into how Pgp binds diverse compounds (Loo and Clarke, 2000; Loo et al., 2009; Aller et al., 2009; Alam et al., 2019; Nosol et al., 2020; Chufan et al., 2015), but how they are translocated through the membrane has remained elusive. Here, we covalently attached a cyclic substrate to discrete sites of Pgp and determined multiple complex structures in inward- and outward-facing states by cryoEM. In conjunction with molecular dynamics simulations, our structures trace the substrate passage across the membrane and identify conformational changes in transmembrane helix 1 (TM1) as regulators of substrate transport. In mid-transport conformations, TM1 breaks at glycine 72. Mutation of this residue significantly impairs drug transport of Pgp in vivo, corroborating the importance of its regulatory role. Importantly, our data suggest that the cyclic substrate can exit Pgp without the requirement of a wide-open outward-facing conformation, diverting from the common efflux model for Pgp and other ABC exporters. The substrate transport mechanism of Pgp revealed here pinpoints critical targets for future drug discovery studies of this medically relevant system.

Sub-chronic exposure to hexaconazole affects the lipid metabolism of rats through mTOR-PPAR-γ/SREBP1 signaling pathway mediated by oxidative stress.

Hexaconazole (Hex) is a widely used and high frequency detected triazole fungicide in agricultural products and environment which may pose potential toxicity to the nontargeted organisms. Hex had been reported to affect lipid homeostasis while the mechanism was undefined. This study aims to explore the characteristic lipidomic profiles and clarify the underlying signaling pathways of Hex-induced lipid metabolism disorder in rat liver. The results showed that sub-chronic exposure to environmental related concentrations of Hex caused histopathological changes, oxidative stress, fat accumulation, lipid biochemical parameter increase in rats. Moreover, the untargeted lipidomic analysis showed that the levels of TAG, PC, and PE and the pathway of glycerophospholipid metabolism were heavily altered by Hex. We further analyzed the lipid metabolism related genes and proteins which revealed that Hex exposure increased amount of lipogenesis by activating oxidative stress-mediated mTOR-PPAR-γ/SREBP1 signaling pathways. The imbalance of lipid homeostasis induced by Hex exposure might further lead to obesity, cardiovascular diseases (CVDs), and hyperlipidemia. Our results provided systematic and comprehensive evidence for the mechanism of Hex-induced lipid metabolism disorder at environmental concentrations and supplied a certain basis for its health risks assessment.

Mechanistic insights into nitrogen-induced changes in pasting characteristics of rice during storage based on proteomics analysis.

Nitrogen application delays rice quality deterioration due to changes in its pasting characteristics; however, the underlying mechanisms remain unclear. Using a label-free quantitative proteomics approach, we identified differentially expressed proteins (DEPs) during storage in paddy rice treated with different nitrogen levels. On combining the changes in physiological indicators, high-nitrogen treatment was found to downregulate ß-1,3-glucanase, reduce the decomposition of cell wall components, downregulate three proteins involved in starch metabolism, decrease the range of the amylose content and increase the range of the amylopectin, upregulate three proteins related to the lysosomal pathway, and enhance glutelin degradation. In addition, it upregulated three proteins related to flavonoid synthesis, which enhanced the stress response ability of rice, thereby contributing to the stability of biological macromolecules. The discovery of these key DEPs provides potential targets for further control over the deterioration of crop seed storage quality.

Co-exposure of heavy metals in rice and corn reveals a probabilistic health risk in Guizhou Province, China.

The adverse effects of heavy metals have arousing concern in the high geological background area, especially in southwestern Guizhou, China. However, the pollution status of heavy metals are still unclear when exposed to rice and corn in Guizhou province. Therefore, the concentration, pollution level, spatial distribution, and probabilistic health risks of Ni, Cr, Pb, Cu, and Zn are estimated in rice and corn. A total of 241 samples (117 for rice and 124 for corn) were collected from Guizhou province and measured by a method of inductively coupled plasma-mass spectrometry (ICP-MS). The results showed that rice and corn were contaminated with Ni and Cr. High concentrations of Ni were presented in the southeast of rice. It indicated that 22.0 % of rice samples were contaminated with Ni. HI values for children and adults exceeded 1.0 in rice and corn, suggesting that humans might be subject to probabilistic non-carcinogenic risks. FTCR demonstrated that rice and corn might cause probabilistic carcinogenic risks to children and adults, which were both greatly higher than 1.0 × 10-4. Moreover, the contributions of Ni to the HI and FTCR were the highest for adults and children. Therefore, more attention should be paid to the exposure of heavy metals in rice and corn, especially in Ni. The results would provide a novel prospective for pollution control and be helpful for environmental regulation.

Home-produced eggs: An important pathway of methylmercury exposure for residents in mercury mining areas, southwest China.

In light of the documented elevated concentrations of total mercury (Hg) and methylmercury (MeHg) in poultry originating from Hg-contaminated sites, a knowledge gap persists regarding the levels of Hg found in home-produced eggs (HPEs) and the associated dietary exposure risks in regions affected by Hg mining. To address this knowledge gap, a comprehensive investigation was undertaken with the primary objectives of ascertaining the concentrations of THg and MeHg in HPEs and evaluating the potential hazards associated with the consumption of eggs from the Wanshan Hg mining area in Southwest China. The results showed that THg concentrations in HPEs varied within a range of 10.5-809 ng/g (with a geometric mean (GM) of 64.1 ± 2.7 ng/g), whereas MeHg levels spanned from 1.3 to 291 ng/g (GM, 23.1 ± 3.4 ng/g). Remarkably, in half of all eggs, as well as those collected from regions significantly impacted by mining activities, THg concentrations exceeded the permissible maximum allowable value for fresh eggs (50 ng/g). Consumption of these eggs resulted in increased exposure risks associated with THg and MeHg, with GM values ranging from 0.024 to 0.17 µg/kg BW/day and 0.0089-0.066 µg/kg BW/day, respectively. Notably, the most substantial daily dosage was observed among children aged 2-3 years. The study found that consuming HPEs could result in a significant IQ reduction of 34.0 points for the whole mining area in a year. These findings highlight the potential exposure risk, particularly concerning MeHg, stemming from the consumption of local HPEs by residents in mining areas, thereby warranting serious consideration within the framework of Hg exposure risk assessment in mining locales.

Chitosan Enhances Low-Dosage Difenoconazole to Efficiently Control Leaf Spot Disease in Pseudostellaria heterophylla (Miq.) Pax.

Pseudostellaria heterophylla (Miq.) Pax is a popular clinical herb and nutritious health food. However, leaf spot disease caused by fungal pathogens frequently occurs and seriously influences the growth, quality, and yield of P. heterophylla. In this work, the field control roles of difenoconazole, chitosan, and their combination in the leaf spot disease in P. heterophylla and their effects on the disease resistance, photosynthetic capacity, medicinal quality, and root yield of P. heterophylla are investigated. The results manifest that 37% difenoconazole water-dispersible granule (WDG) with 5000-time + chitosan 500-time dilution liquid had a superior control capacity on leaf spot disease with the control effects of 91.17%~88.19% at 15~30 days after the last spraying, which significantly (p < 0.05) exceeded that of 37% difenoconazole WDG 3000-time dilution liquid and was significantly (p < 0.01) higher than that of 37% difenoconazole WDG 5000-time dilution liquid, chitosan 500-time dilution liquid, or chitosan 1000-time dilution liquid. Simultaneously, this combination could more effectively enhance the disease resistance, photosynthetic capacity, medicinal quality, and tuberous root yield of P. heterophylla compared to when these elements were applied alone, as well as effectively reduce difenoconazole application. This study emphasizes that chitosan combined with a low dosage of difenoconazole can be proposed as a green, efficient, and alternative formula for controlling leaf spot disease in P. heterophylla and enhancing its resistance, photosynthesis, quality, and yield.

Lipid environment determines the drug-stimulated ATPase activity of P-glycoprotein.

P-glycoprotein (Pgp) is a multidrug transporter that uses the energy from ATP binding and hydrolysis to export from cells a wide variety of hydrophobic compounds including anticancer drugs, and mediates the bioavailability and pharmacokinetics of many drugs. Lipids and cholesterol have been shown to modulate the substrate-stimulated ATPase activity of purified Pgp in detergent solution and the substrate transport activity after reconstitution into proteoliposomes. While lipid extracts from E. coli, liver or brain tissues generally support well Pgp's functionality, their ill-defined composition and high UV absorbance make them less suitable for optical biophysical assays. On the other hand, studies with defined synthetic lipids, usually the bilayer-forming phosphatidylcholine with or without cholesterol, are often plagued by low ATPase activity and low binding affinity of Pgp for drugs. Drawing from the lipid composition of mammalian plasma membranes, we here investigate how different head groups modulate the verapamil-stimulated ATPase activity of purified Pgp in detergent-lipid micelles and compare them with components of E. coli lipids. Our general approach was to assay modulation of verapamil-stimulation of ATPase activity by artificial lipid mixtures starting with the bilayer-forming palmitoyloyl-phosphatidylcholine (POPC) and -phosphatidylethanolamine (POPE). We show that POPC/POPE supplemented with sphingomyelin (SM), cardiolipin, or phosphatidic acid enhanced the verapamil-stimulated activity (Vmax) and decreased the concentration required for half-maximal activity (EC50). Cholesterol (Chol) and more so its soluble hemisuccinate derivative cholesteryl hemisuccinate substantially decreased EC50, perhaps by supporting the functional integrity of the drug binding sites. High concentrations of CHS (>15%) resulted in a significantly increased basal activity which could be due to binding of CHS to the drug binding site as transport substrate or as activator, maybe acting cooperatively with verapamil. Lastly, Pgp reconstituted into liposomes or nanodiscs displayed higher basal activity and sustained high levels of verapamil stimulated activity. The findings establish a stable source of artificial lipid mixtures containing either SM and cholesterol or CHS that restore Pgp functionality with activities and affinities similar to those in the natural plasma membrane environment and will pave the way for future functional and biophysical studies.

Low dosage fluorine ameliorates the bioaccumulation, hepatorenal dysfunction and oxidative stress, and gut microbiota perturbation of cadmium in rats.

Many "hot spot" geographic areas around the world with soils and crops co-polluted with cadmium (Cd) and fluorine (F), two of the most representative pollutants in the environment. However, it still exists argumentative on the dose-effect relationship between F and Cd so far. To explore this, a rat model was established to evaluate the effects of F on Cd-mediated bioaccumulation, hepatorenal dysfunction and oxidative stress, and the disorder of intestinal microbiota as well. 30 healthy rats were randomly assigned to Control group (C group), Cd 1 mg/kg (Cd group), Cd 1 mg/kg and F 15 mg/kg (L group), Cd 1 mg/kg and F 45 mg/kg (M group), and Cd 1 mg/kg and F 75 mg/kg (H group) for 12 weeks by gavage. Our results showed that Cd exposure could accumulate in organs, cause hepatorenal function damage and oxidative stress, and disorder of gut microflora. However, different dosages of F showed various effects on Cd-induced damages in liver, kidney, and intestine, and only the low supplement of F showed a consistent trend. After low supplement of F, Cd levels were declined by 31.29% for liver, 18.31% for kidney, and 2.89% for colon, respectively. The serum aspartate aminotransferase (AST), blood urea nitrogen (BUN), creatinine (Cr), and N-acetyl-ß-glucosaminidase (NAG) were significantly reduced (p < 0.01); The activity of superoxide dismutase (SOD) was elevated and mRNA expression level of NAD(P)H quinone oxidoreductase 1 (NQO1) was decreased in the liver and kidney (p < 0.05). Moreover, low F dosage up-regulated the abundance of Lactobacillus from 15.56% to 28.73% and the 6.23% of F/B ratio was declined to 3.70%. Collectively, this highlights that low dosage of F might be a potential strategy to ameliorate the hazardous effects by Cd-exposed in the environment.

Bacillus cereus WL08 immobilized on tobacco stem charcoal eliminates butylated hydroxytoluene in soils and alleviates the continuous cropping obstacle of Pinellia ternata.

Butylated hydroxytoluene (BHT), as an emerging contaminant in ecosystems, has potential influences on animals, aquatic organisms, and public health, and has been proven to be a major allelochemical of Pinellia ternata. In this study, Bacillus cereus WL08 was used to rapidly degrade BHT in liquid culture. Strain WL08 immobilized on tobacco stem charcoal (TSC) particles notably accelerated BHT removal in contract to its free cells, and exhibited excellent reutilization and storage capacities. The optimal removal parameters of TSC WL08 were ascertained to be pH 7.0, 30 °C, 50 mg L-1 BHT and 0.14 mg L-1 TSC WL08. Moreover, TSC WL08 significantly accelerated the degradation of 50 mg L-1 BHT in sterile and non-sterile soils compared to that of free WL08 or natural dissipation, and notably shortened their half-lives by 2.47- or 362.14- fold, and 2.20- or 14.99- fold, respectively. Simultaneously, TSC WL08 was introduced into the continuous cropping soils of P. ternata, which accelerated the elimination of allelochemical BHT, and notably enhanced the photosynthesis, growth, yield, and quality of P. ternata. This study provides new insights and strategies for the rapid in situ remediation of BHT-polluted soils and effective alleviation of P. ternata cropping obstacles.

Stereoselective Toxicokinetic and Distribution Study on the Hexaconazole Enantiomers in Mice.

Hexaconazole (Hex) has been widely used in agricultural products, and its residues may pose a potential risk to human health. However, the metabolic behavior of Hex enantiomers in mammal organisms is still unknown, which is important for evaluating the differences in their toxicity. In this study, the distribution of S-(+)- and R-(-)-Hex in mice was detected by an ultra-high performance liquid chromatography coupled with tandem mass spectrometry (UPLC-MS/MS), and the mechanism differences in the toxicokinetic behavior were analyzed by molecular docking. Good linearities, accuracies, and precisions were achieved for S-(+)- and R-(-)-Hex, with recoveries of 88.7~104.2% and RSDs less than 9.45% in nine tissues of mice. This established method was then used to detect the toxicokinetic of Hex enantiomers in mice after oral administration within 96 h. The results showed that the half-lives of S-(+)- and R-(-)-Hex were 3.07 and 3.71 h in plasma. Hex was mainly accumulated in the liver, followed by the kidneys, brain, lungs, spleen, and heart. The enantiomeric fraction (EF) values of Hex enantiomers in most of the samples were below 1, indicating that S-(+)-Hex decreased faster than its antipode. The molecular docking showed that the binding of S-(+)-Hex with P450arom was much more stable than R-(-)-Hex, which verified the fact that S-(+)-Hex was prefer to decrease in most of the tissues. The results of this study could be helpful for further evaluating the potential toxic risk of Hex enantiomers and for the development and usage of its pure monomer.

Enantioselective toxicity effect and mechanism of hexaconazole enantiomers to human breast cancer cells.

The toxicity effects of chiral pesticides on living organisms have attracted an increasing public attention. This study aims to investigate the toxicity effect and mechanism of hexaconazole (HEX) to human breast cancer cell (MCF-7) at enantiomer levels. HEX exposure obviously inhibited cells activities in a dose-dependent manner. Under the conditions of VIP >1 and p < 0.05, a total of 255 and 177 differential metabolites (DMs), 17 and 15 amino acid- and lipid-related metabolic pathways were disturbed after (+)-HEX and (-)-HEX exposure, respectively. HEX exposure may affect cell membrane function, signal transduction, and cell differentiation. We further investigated the mechanism of enantioselective differences by using molecular docking which showed that CYP17A1 was the main enzyme that leading to endocrine disrupting effects with the binding energy of -6.30 and -6.08 kcal/mol compared to CYP19A1 enzyme which were -5.81 and -5.93 kcal/mol for (+)-HEX and (-)-HEX, respectively. The docking results explained the reasons why (+)-HEX achieved higher cytotoxicity and induced more seriously metabolic profiles than its antipode. These findings could provide a new insight to understand the enantioselective cytotoxicity effect and mechanism of HEX and will be conducive to assessing its risk to human health at enantiomer levels.

Soil exposure is the major fluoride exposure pathways for residents from the high-fluoride karst region in Southwest China.

In the karst areas of southwest China, soil fluoride levels are higher than in China (478 mg kg-1) and world (200 mg kg-1). High levels of F in the environment might pose a health risk to humans. The comprehensive exposure risk must be studied in this area. Herein, samples of crops and soil were collected from Bijie City, a typical karst area in southwest China, to investigate the pollution level and evaluate the comprehensive F exposure risk. The single-factor index (PFw) and the geological accumulation index (Igeo) were used. The hazard index (HI) was applied to assess exposure risk from multiple exposure routes. The results revealed that there is considerable F contamination in soil and crops in the study area. Average soil total fluorine (Ft) was 1139.13 mg kg-1, and soil water soluble F (Fw) was 3.792 mg kg-1. In corn, rice, wheat, and potatoes, F contents were 1.167-9.585, 1.222-6.698, 1.587-9.976, and 1.797-9.143 mg kg-1, respectively. The mean values of HI were 4.45 and 2.42 for children and adults, respectively, > 1, showing potential health risk exists. Youngsters are at a greater exposure risk than adults. From the results of contribution ratios of different exposure routes for health risk, the major exposure risk was determined to be from soil exposure. Based on this, we suggest that risk managers mainly strive to control the soil fluoride level and implement the risk education and communication.

An Optimization Design Method of Rigid-Flexible Soft Fingers Based on Dielectric Elastomer Actuators.

The soft gripper has received extensive attention, due to its good adaptability and flexibility. The dielectric elastomer (DE) actuator as a flexible electroactive polymer that provides a new approach for soft grippers. However, they have the disadvantage of having a poor rigidity. Therefore, the optimization design method of a rigid-flexible soft finger is presented to improve the rigidity of the soft finger. We analyzed the interaction of the rigid and soft materials, using the finite element method (FEM), and researched the influence of the parameters (compression of the spring and pre-stretching ratio of the DE) on the bending angle. The optimal parameters were obtained using the FEM. We experimentally verified the accuracy of the proposed method. The maximum bending angle is 19.66°. Compared with the theoretical result, the maximum error is 3.84%. Simultaneously, the soft gripper with three fingers can grasp various objects and the maximum grasping quality is 11.21 g.

Spatial distribution and risk assessment of fluorine and cadmium in rice, corn, and wheat grains in most karst regions of Guizhou province, China.

The pollution status of crops planted in Guizhou province of Southwestern China with high background values of Fluorine (F) and Cadmium (Cd) has attracted people's concern. The present study aimed to investigate the spatial distributions of F and Cd in rice, corn and wheat grains, and further evaluate their health risks to residents in Guizhou province. The contents of F and Cd were measured by fluoride ion-selective electrode and inductively coupled plasma mass spectrometry (ICP-MS) methods, respectively. Additionally, the inverse distance weighted (IDW) technique was conducted to analyze spatial distribution, and the health risk was estimated by target hazard quotient (THQ) and hazardous index (HI). The results indicate that Cd contents in samples varied from 0.000 to 0.463 for rice, 0.000 to 0.307 for corn, and 0.012 to 0.537 (mg/kg) for wheat, while F contents ranged from 0.825 to 5.193 (rice), 0.946 to 8.485 (corn), and 0.271 to 9.143 (wheat) mg/kg. The Cd exceeding ratios were 11.600% for rice, 13.500% for corn, and 45.100% for wheat grains, respectively. In terms of spatial distribution, high levels of F and Cd in rice were found in the northern and central in Guizhou, while Cd in corn was distributed in the eastern and F in corn were distributed in the west area of Guizhou. Moreover, the high levels of F and Cd in wheat were distributed in the western and eastern areas. The mean carcinogenic risks (R) of Cd in rice, corn, and wheat in children were 4.150 × 10-4, 1.670 × 10-4 and 3.470 × 10-4, respectively, and that in adults were 3.430 × 10-4, 0.471 × 10-4, and 2.190 × 10-4, respectively. The HI for adults in rice, corn and wheat grains were 0.756, 0.154, and 0.514, respectively, and that for children were 0.913, 0.549, and 0.814, respectively. Collectively, the potential risks produced by F and Cd to the local residents should not be ignored.

Co-exposure of potentially toxic elements in wheat grains reveals a probabilistic health risk in Southwestern Guizhou, China.

Bijie is located at a typical karst landform of Southwestern Guizhou, which presented high geological background values of potentially toxic elements (PTEs). Recently, whether PTE of wheat in Bijie is harmful to human health has aroused people's concern. To this end, the objectives of this study are to determine the concentrations of PTE [chromium (Cr), nickel (Ni), arsenic (As), lead (Pb), cadmium (Cd), and fluorine (F)] in wheat grains, identify contaminant sources, and evaluate the probabilistic risks to human beings. A total of 149 wheat grain samples collected from Bijie in Guizhou were determined using the inductively coupled plasma mass spectrometer (ICP-MS) and fluoride-ion electrode methods. The mean concentrations of Cr, Ni, As, Cd, Pb, and F were 3.250, 0.684, 0.055, 0.149, 0.039, and 4.539 mg/kg, respectively. All investigated PTEs met the standard limits established by the Food and Agriculture Organization except for Cr. For the source identification, Cr and Pb should be originated from industry activities, while Ni, As, and Cd might come from mixed sources, and F was possibly put down to the high geological background value. The non-carcinogenic and carcinogenic health risks were evaluated by the probabilistic approach (Monte Carlo simulation). The mean hazard quotient (HQ) values in the three populations were lower than the safety limit (1.0) with the exception of As (children: 1.03E+00). However, the mean hazard index (HI) values were all higher than 1.0 and followed the order: children (2.57E+00) > adult females (1.29E+00) > adult males (1.12E+00). In addition, the mean carcinogenic risk (CR) values for Cr, As, Pb, and Cd in three populations were all higher than 1E-06, which cannot be negligible. The mean threshold CR (TCR) values were decreased in the order of children (1.32E-02) > adult females (6.61E-03) > adult males (5.81E-03), respectively, all at unacceptable risk levels. Moreover, sensitivity analysis identified concentration factor (C W ) as the most crucial parameter that affects human health. These findings highlight that co-exposure of PTE in wheat grains revealed a probabilistic human health risk. Corresponding measures should be undertaken for controlling pollution sources and reducing the risks for the local populace.

Accumulation and risk assessment of heavy metals in rice: a case study for five areas of Guizhou Province, China.

In the present study, the concentration and accumulation abilities of five heavy metals (Cd, Hg, As, Pb, Cr) in rice were assessed and their human health risk to local citizens had been evaluated. Soil and rice samples (125 samples) were collected from Guiyang (GY), Qiannan (QN), Bijie (BJ), Tongren (TR), and Zunyi (ZY) in Guizhou Province. Heavy metals were measured by inductively coupled plasma-mass spectrometry (ICP-MS) after microwave digestion. The mean concentrations of Cd, Hg, As, Pb, and Cr were 0.58, 0.65, 12.31, 38.70, and 87.30 mg/kg in soil and were 0.05, 0.005, 0.11, 0.07, and 0.34 mg/kg in rice, respectively. The bioconcentration factors (BCF) decreased with the order Cd > Hg > As > Cr > Pb. Non-carcinogenic risk in this study was evaluated using the method of the hazard quotient (HQ) and hazard index (HI). The mean HQ values for Cd, Hg, Pb, and Cr were all lower than the standard limit (1.0) for children and adults, except As with the mean HQ for children of 2.79. The mean HI values for children and adults were 4.22 and 1.42, which exceeded 1.0. The mean carcinogenic risk (CR) values of As and Pb for children and adults were higher than the upper limit of the acceptable range (1 × 10-4) established by the United States Environmental Protection Agency (USEPA). In a conclusion, the non-carcinogenic and carcinogenic risks induced by heavy metals for children were higher than that for adults. This study revealed that consumption of rice in study areas may pose potential non-carcinogenic and carcinogenic risks to humans, and As was the largest contributor.

Association Between Circulating Cell-Free DNA Level at Admission and the Risk of Heart Failure Incidence in Acute Myocardial Infarction Patients.

Plasma cell-free DNA (cfDNA) was elevated in patients with acute myocardial infarction (AMI) or heart failure (HF). However, whether cfDNA could serve as a predictor for risk of HF after AMI remains unknown. In this study, we conducted a pilot prospective cohort study in which 98 AMI patients were enrolled from a single center to assess the association between cfDNA levels at admission and risk of HF in an AMI population. Patients with cfDNA above the median level (14.39 ng/mL) showed higher low-density lipoprotein cholesterol, cardiac troponin I (cTnI), and soluble suppression of tumorigenicity 2 (sST2) levels compared with patients below the median. cfDNA was positively correlated with cTnI (r = 0.377, p < 0.001) and sST2 (r = 0.443, p < 0.001). Within a median follow-up of about 345 days, 46 patients (52.6%) developed HF. Multivariate Cox analysis showed that a higher cfDNA (above the cutoff value: 9.227 ng/mL) was an effective risk predictor (C-index = 0.74, 95% confidence interval [CI]: 0.733-0.748) for HF incidence after AMI (adjusted hazard ratio [HR]: 2.805; 95% CI: 1.087-7.242; p = 0.033). Moreover, a linear association was observed between cfDNA and risk of HF incidence adjusted for by age, gender, and history of chronic kidney disease (p for linear trend = 0.044). Taken together, the cfDNA levels at admission are associated with the incidence of HF in AMI patients. A positive correlation between cfDNA and the fibrotic factor sST2 was proved, but the underlying mechanisms require further study.