Determination of 90Sr and 210Pb in food samples by liquid scintillation counting after sequential separation with an extraction chromatographic column.

90Sr and 210Pb are considered to be key radionuclides in internal exposure resulting from dietary intake, however, the established methods employed for their detection are time-comsuming. A method for the sequential separation of 90Sr and 210Pb using a Sr·spec resin by LSC measurement is developed, which is highly suitable for food safety monitoring as its minimal sample requirements. The sequential separation of Sr and Pb from the sample was using 0.05 mol/L HNO3 and 0.05 mol/L C6H5O7(NH4)3. The chemical recoveries of Sr and Pb measured using ICP-OES were 72-83% and 80-88%, respectively. The minimum detectable activities of 90Sr and 210Pb in the food sample were 36.2 mBq/kg and 28.6 mBq/kg, respectively, obtained from a 0.1 kg fresh sample and 300 min counting time. The method was validated using reference materials and compared with other methods. The feasibility of the developed method for other highly complex food matrices needs further investigation.

Simultaneous determination of 226Ra and 228Ra in food samples using liquid scintillation counting.

The 228Ra and 226Ra isotopes of radium are significant contaminants in food, raising public concern because of their radiotoxicity. Several methods are available for determining 228Ra and 226Ra. However, the application of these procedures is not focused on food but only on water and environmental matrices. In this study, a cost-effective method for the simultaneous determination of 226Ra and 228Ra radioactivity in food samples using liquid scintillation counting was developed. The overall efficiencies of 226Ra and 228Ra in the food samples are 69.4-78.4% and 30.1-35.8%, respectively. The minimum detectable activities of 226Ra and 228Ra are 11.3 mBq/g and 33.4 mBq/g, respectively, in our food sample, obtained using a 1.0 g ash sample and 60 min of counting time. The method was validated using IAEA-certified reference materials and compared with data obtained using gamma spectrometry in tea, kelp, and oyster samples.

Construction of the machine learning-based live birth prediction models for the first in vitro fertilization pregnant women.

BACKGROUND: This study was to conduct prediction models based on parameters before and after the first cycle, respectively, to predict live births in women who received fresh or frozen in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) for the first time. METHODS: This retrospective cohort study population consisted of 1,857 women undergoing the IVF cycle from 2019 to 2021 at Huizhou Municipal Central Hospital. The data between 2019 and 2020 were completely randomly divided into a training set and a validation set (8:2). The data from 2021 was used as the testing set, and the bootstrap validation was carried out by extracting 30% of the data for 200 times on the total data set. In the training set, variables are divided into those before the first cycle and after the first cycle. Then, predictive factors before the first cycle and after the first cycle were screened. Based on the predictive factors, four supervised machine learning algorithms were respectively considered to build the predictive models: logistic regression (LR), random forest (RF), extreme gradient boosting (XGBoost), and light gradient boosting machine (LGBM). The performances of the prediction models were evaluated by the area under the receiver operator characteristic curve (AUC), sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy. RESULTS: Totally, 851 women (45.83%) had a live birth. The LGBM model showed a robust performance in predicting live birth before the first cycle, with AUC being 0.678 [95% confidence interval (CI): 0.651 to 0.706] in the training set, 0.612 (95% CI: 0.553 to 0.670) in the validation set, 0.634 (95% CI: 0.511 to 0.758) in the testing set, and 0.670 (95% CI: 0.626 to 0.715) in the bootstrap validation. The AUC value in the training set, validation set, testing set, and bootstrap of LGBM to predict live birth after the first cycle was 0.841 (95% CI: 0.821 to 0.861), 0.816 (95% CI: 0.773 to 0.859), 0.835 (95% CI: 0.743 to 0.926), and 0.839 (95% CI: 0.806 to 0.871), respectively. CONCLUSION: The LGBM model based on the predictive factors before and after the first cycle for live birth in women showed a good predictive performance. Therefore, it may assist fertility specialists and patients to adjust the appropriate treatment strategy.

Simvastatin Inhibits Endometrial Cancer Malignant Behaviors by Suppressing RAS/Mitogen-Activated Protein Kinase (MAPK) Pathway-Mediated Reactive Oxygen Species (ROS) and Ferroptosis.

This paper was designed to explore the function of simvastatin as a chemotherapeutic drug on the endometrial cancer (EC) cell proliferation, invasion, and ferroptosis. Firstly, a number of in vitro experiments were conducted to determine the impact of different treatments of simvastatin on the Ishikawa cell invasion, proliferation, and colony formation. The concentration of DCFH-DA-labeled reactive oxygen species (ROS) in cells was assessed by flow cytometry. Enzyme-linked immunosorbent assay (ELISA) was performed to examine the intracellular contents of Fe2+, malondialdehyde (MDA), and glutathione (GSH). Additionally, Western blot was utilized to measure the expression level of RAS/mitogen-activated protein kinase (MAPK)-related proteins and ferroptosis-related proteins in cells. The results showed that simvastatin at 10 µM and 15 µM apparently suppressed the proliferation of Ishikawa cells, colony formation, and invasion ability of Ishikawa cells, and upregulated the level of MDA and ROS, but downregulated the level of GSH. Besides, 10 µM and 15 µM of simvastatin promoted cell ferroptosis (up-regulation of Fe2+ and TRF 1 protein level; down-regulation of SLC7A11 and FPN protein level) and lowered the RAS, p-MEK, and ERK protein level. Furthermore, experiments also revealed that the inhibitory effects of simvastatin on Ishikawa cell proliferation, colony formation, and invasion, as well as the promoting effects on oxidation and ferroptosis were reversed. All in all, simvastatin reduces the RAS/MAPK signaling pathway to inhibit Ishikawa cell proliferation, colony formation, and invasion, and promote cell oxidation and ferroptosis. This paper demonstrates the potential of simvastatin as a new anticancer drug for EC.

Design of functionalized magnetic silica multi-core composite nanoparticles for synergistic magnetic hyperthermia/radiotherapy in cancer cells.

Nanomaterials in particular the magnetic nanoparticles (MNPs) offer tremendous potential for cancer treatment due to their unique intrinsic properties. Combining materials with a variety of functional groups, and forming a multifunctional nanosystem to overcome the limitations of monotherapy for cancer treatment has always been a research focus with notable difficulties. Considering the many challenges faced by radiotherapy and hyperthermia, in this study, we designed a rational strategy for magnetic hyperthermia using Fe3O4@SiO2@Sec2@FA nanoparticles as a novel nano-radiosensitizer to simultaneously enhance the therapeutic effects of radiotherapy in the future. Fe3O4@SiO2 core-shell structured nanoparticles were synthesized with an appropriate silica layer thickness to maintain good saturation magnetization. The as-prepared Fe3O4@SiO2@Sec2@FA nanoparticles had the specific absorption rate (SAR)value of 57 W/g, which was below the clinically acceptable alternating magnetic field value of 4.9 × 109 Am-1s-1, indicating good heat generation efficiency (the temperature level ΔT=6-10 °C). Moreover, Folate-modified nanoparticles exhibited approximately 6-fold higher cellular internalization of Hela cells with no obvious cytotoxicity for the Hela and MDA-MB-231 cells, and lower cytotoxicity for the HUVECs in a concentration range of 0-150 µg/mL. In addition, these nanoparticles were modified on the silica surface by L-selenocystine, which could enhance the elimination of tumor cells by producing reactive oxygen species under X-rays, resulting in a novel radiosensitization effect. Therefore, the as-prepared Fe3O4@SiO2@Sec2@FA nanoparticles with good biocompatibility and active targeting would possess synergistic magnetic hyperthermia/radiotherapy effect.

OTUD7B deubiquitinates SQSTM1/p62 and promotes IRF3 degradation to regulate antiviral immunity.

Deubiquitination plays an important role in the regulation of the crosstalk between macroautophagy/autophagy and innate immune signaling, yet its regulatory mechanisms are not fully understood. Here we identify the deubiquitinase OTUD7B as a negative regulator of antiviral immunity by targeting IRF3 (interferon regulatory factor 3) for selective autophagic degradation. Mechanistically, OTUD7B interacts with IRF3, and activates IRF3-associated cargo receptor SQSTM1/p62 (sequestosome 1) by removing its K63-linked poly-ubiquitin chains at lysine 7 (K7) to enhance SQSTM1 oligomerization. Moreover, viral infection increased the expression of OTUD7B, which forms a negative feedback loop by promoting IRF3 degradation to balance type I interferon (IFN) signaling. Taken together, our study reveals a specific role of OTUD7B in mediating the activation of cargo receptors in a substrate-dependent manner, which could be a potential target against excessive immune responses.Abbreviations: Baf A1: bafilomycin A1; CGAS: cyclic GMP-AMP synthase; DDX58/RIG-I: DExD/H-box helicase 58; DSS: dextran sodium sulfate; DUBs: deubiquitinating enzymes; GFP: green fluorescent protein; IFN: interferon; IKKi: IKBKB/IkappaB kinase inhibitor; IRF3: interferon regulatory factor 3; ISGs: interferon-stimulated genes; MAVS: mitochondrial antiviral signaling protein; MOI: multiplicity of infection; PAMPs: pathogen-associated molecular patterns; SeV: Sendai virus; siRNA: small interfering RNA; SQSTM1/p62: sequestosome 1; STING1: stimulator of interferon response cGAMP interactor 1; TBK1: TANK binding kinase 1; Ub: ubiquitin; WT: wild-type; VSV: vesicular stomatitis virus.

Levels and Distributions of 210Pb and 210Po in Selected Seafood Samples in China and Assessment of Related Dose to Population.

In this study, the activity concentrations levels of 210Pb and 210Po in the edible portions of eight seafood samples collected from the Fujian coast of China were determined. The activity concentrations ranged from 0.74 ± 0.08 to 12.6 ± 1.0 Bq/kg for 210Po and from the minimum detectable limit (MDL, 0.80 Bq/kg) to 11. 7 ± 1.1 Bq/kg for 210Pb. The 210Po activity concentration in all the fish organs ranged from 0.68 to 204 Bq/kg (w.w.), and the 210Po activity was mainly concentrated in the stomach, spleen, heart, liver, gonad, and intestine samples. The 210Pb activity concentration in all the fish organs ranged from the MDL to 15.2 Bq/kg (w.w.), and the 210Pb activity was concentrated in the head, fish scale, and gill samples. The annual effective ingestion doses ranged from 82.8 to 255 µSv/a for all age groups, and the lifetime risk of cancers were estimated. Both the effective ingestion doses and cancer risk to humans were within the acceptable ranges.

Diastolic dysfunction and impaired cardiac output reserve in dysmetabolic nonhuman primate with proteinuria.

BACKGROUND: Cardiorenal complications are common in patients with dysmetabolism and diabetes. The present study aimed to examine if a nonhuman primate (NHP) model with spontaneously developed metabolic disorder and diabetes develops similar complications to humans, such as proteinuria and cardiac dysfunction at resting condition or diminished cardiac functional reserve following dobutamine stress echocardiography (DSE). METHODS AND RESULTS: A total of 66 dysmetabolic and diabetic cynomolgus (Macaca fascicularis) NHPs were enrolled to select 19 NHPs (MetS) with marked metabolic disorders and diabetes (fasting blood glucose: 178 ±â€¯18 vs. 61 ±â€¯3 mg/dL) accompanied by proteinuria (ACR: 134 ±â€¯34 vs. 1.5 ±â€¯0.4 mg/mmol) compared to 8 normal NHPs (CTRL). Under resting condition, MetS NHPs showed mild left ventricular (LV) diastolic dysfunction (E/A: 1 ±â€¯0.06 vs. 1.5 ±â€¯0.13), but with preserved ejection fraction (EF: 65 ±â€¯2 vs. 71 ±â€¯3%) compared to CTRL. DSE with an intravenous infusion of dobutamine at ascending doses (5, 10, 20, 30 and 40 µg/kg/min, 7 min for each dose) resulted in a dose-dependent increase in cardiac function, however, with a significantly diminished magnitude at the highest dose of dobutamine infusion (40 µg/kg/min) in both diastole (E/A: -12 ±â€¯3 vs. -38 ±â€¯5%) and systole (EF: 25 ±â€¯3 vs. 33 ±â€¯5%) as well as ~42% reduced cardiac output reserve (COR: 63 ±â€¯8 vs. 105 ±â€¯18%, p < 0.02) in the MetS compared to CTRL NHPs. CONCLUSION: These data demonstrate that MetS NHPs with cardiorenal complications: proteinuria, LV diastolic dysfunction and preserved LV systolic function under resting conditions displayed compromised cardiac functional reserve under dobutamine stress. Based on these phenotypes, this NHP model of diabetes with cardiorenal complications can be used as a highly translational model mimic human disease for pharmaceutical research.

Simultaneous determination of 210Pb and 210Po in seafood samples using liquid scintillation counting.

The measurement of 210Pb and 210Po in seafood samples has attracted tremendous interest because of their radiotoxicity. In this study, a fast and cost-efficient method for the simultaneous determination of 210Pb and 210Po in seafood samples by ultralow-level liquid scintillation counting after separation on a Sr•spec column was developed. The recoveries of 210Pb and 210Po were ~70% and ~85%, respectively. The minimum detectable activity of the proposed method for 210Pb and 210Po was 3.85 Bq/kg and 1.50 Bq/kg, respectively, which is suitable for the determination of 210Pb and 210Po in seafood samples. The radiochemical procedure was validated by measuring 210Pb and 210Po activity concentrations in IAEA-certified reference materials and successfully applied to shrimp and clam samples.

Estimation of Inhaled Effective Doses of Uranium and Thorium for Workers in Bayan Obo Ore and the Surrounding Public, Inner Mongolia, China.

Uranium and thorium are two common natural radioactive elements with high concentrations in Earth's crust. The main aim of this study is to estimate the inhaled effective dose of uranium and thorium caused by a typical radioactive rare earth ore to the occupational population and the surrounding public. The particulate matter (PM) concentrations in the atmosphere of four typical workplaces and one surrounding living area were obtained by a high-flow sampling equipment with a natural cellulose filter membrane. The critical parameter for the inhaled effective dose estimation-the activity median aerodynamic diameter (AMAD)-was determined. The AMAD values of uranium and thorium in the atmosphere PM were 3.36 and 3.64 µm, respectively. The estimated median effective dose caused by inhalation thorium among the occupational population ranged from 15.3 to 269.0 µSv/a, and the corresponding value for the surrounding public was 2.3 µSv/a. All values for the effective dose caused by the inhalation of uranium were in the nSv magnitude.

A Novel Circulating MiRNA-Based Signature for the Diagnosis and Prognosis Prediction of Early-Stage Cervical Cancer.

BACKGROUND: MicroRNAs (miRNAs) have been shown to play a key role in regulating the progression of cervical cancer (CC). This study aimed to develop a circulating miRNA-based molecular signature for the diagnosis and prognosis prediction of early-stage CC. METHODS: This study included 112 patients diagnosed with early-stage CC, 45 patients confirmed with cervical intraepithelial neoplasia (CIN) and 90 healthy subjects. Compared to the normal controls, the expression level of miR-21 was increased, while the levels of miR-125b and miR-370 were decreased in CC in both GSE30656 and The Cancer Genome Atlas (TCGA) cohort. The expression levels and diagnostic value of these candidate miRNAs were then validated through qRT-PCR. Their diagnostic and prognostic values for early-stage CC were further explored. RESULTS: Compared to the patients with CIN and healthy subjects, serum miR-21 was increased, while serum miR-125b and serum miR-370 were reduced in early-stage CC. In addition, combining these molecules yielded good performance for differentiating early-stage CC from CIN or healthy subjects. Moreover, strong association was found between serum miR-21 and lymph node metastasis (LNM) as well as recurrence-free survival of early-stage CC. Similar observations were found for serum miR-125b and serum miR-370. Patients with simultaneously high serum miR-21 + low serum miR-125b + low serum miR-370 suffered a high risk of LNM and recurrence, while those with low serum miR-21 + high serum miR-125b + high serum miR-370 had little risk for LNM and recurrence. CONCLUSIONS: Combining serum miR-21, miR-125b and miR-370 as a miRNA-based signature is promising for the detection and prognosis prediction of early-stage CC.

Monitoring of ultra-trace uranium and thorium in six-grade particles.

The natural radioactive elements uranium(U) and thorium(Th) in atmospheric environment should be given attention, and their particle size distribution and concentration are important for estimating their hazardous effects to the human body. The concentrations of U and Th in 360 aerosol samples collected using six-stage aerosol collector from June - December, 2016 in Beijing were determinated using ICP-MS after acid digestion. The mass concentration ranges of U in PM0.39-0.69, PM0.69-1.3, PM1.3-2.1, PM2.1-4.2, PM4.2-10.2, and PM10.2- reached 0.0030-0.079, 0.0020-0.069, 0.0015-0.095, 0.0053-0.054, 0.0039-0.098, and 0.0083-0.10 ng/m3, respectively. The mass concentration range of Th in PM0.39-0.69, PM0.69-1.3, PM1.3-2.1, PM2.1-4.2, PM4.2-10.2, and PM10.2- amounted to 0.011-0.11, 0.0065-0.11, 0.0026-0.18, 0.0078-0.14, 0.015-0.30, and 0.0021-0.19 ng/m3, respectively. The contents of U and Th in all PM increased from June to December, and the contents in PM2.1 increased more sharply compared with those in other PM. A positive correlation was observed between the concentrations of U and Th and air quality index and relative humidity, whereas a negative correlation was identified between temperature and PM2.1, PM10.2, and total suspended particulates (TSP) after the Spearman-rank correlation test. The formation of PM was affected by meteorological conditions, which concurrently influenced the contents of U and Th in PM. The atmospheric contents of U and Th at night were higher than those in daytime. Compared with Th, the dose contribution of U to the public can be negligible. The median effective dose in public owing to inhalation of natural radioactive U and Th in the atmosphere measures 1.206 µSv/a.

Acetyl-coenzyme A acyltransferase 2 promote the differentiation of sheep precursor adipocytes into adipocytes.

The acetyl CoA acyltransferase 2 (ACAA2) is a key enzyme of the fatty acid oxidation pathway, catalyzing the last step of the mitochondrial beta oxidation, thus playing an important role in the fatty acid metabolism. The purpose of this study was to investigate the effect of knocking out ACAA2 on the expression of genes lipoprteinlipase (LPL), peroxisome proliferator-activated receptor-γ (PPAR-γ), fatty acid synthase, fat mass and obesity-associated gene, adipocyte fatty acid-binding protein (AP2) in precursor adipocytes and their differentiation into adipocytes. The knockout vector was constructed using CRISPR-Cas RNA-guided nuclease technology with an efficiency of 23.80%, and the vector was transfected into precursor adipocyte cells, while an overexpression vector of the ACAA2 gene was also transfected in another group of preadipocytes. Quantitative polymerase chain reaction showed that the expression of the PPAR-γ, LPL, and AP2 was significantly lower in the knockout compared with the overexpression group, while there was no difference in cell growth. After induction of adipocyte precursor cells into adipocytes using dexamethasone, insulin, and IBMX, oil red staining showed a significantly different number of lipid droplets in the knockout group. These results provide a preliminary indication for a possible involvement of the ACAA2 gene in adipocyte differentiation in vitro.

Rapid method for determination of 90Sr in biological samples by liquid scintillation counting after separation on synthesized column.

A simple, rapid and cost-efficient method for determination of activity concentration of 90Sr in biological samples with an extraction chromatographic column (crown ether on teflon powder) and following counted by liquid scintillation counting was developed in this paper. The column retained most of 90Sr while almost all of matrix ions were removed during rinsing steps with 8M nitric acid and finally 90Sr was eluted with deionized water, the chemical recovery of strontium is greater than 60%, almost all of matrix ions were removed by the procedure we reported. Finally the uncertainty was evaluated and minimum detectable activity of this method is 1.28Bq/kg.

CRISPR/Cas9 mediated chicken Stra8 gene knockout and inhibition of male germ cell differentiation.

An efficient genome editing approach had been established to construct the stable transgenic cell lines in the domestic chicken (Gallus gallus domesticus) at present. Our objectives were to investigate gene function in the differentiation process of chicken embryonic stem cells (ESCs) into spermatogonial stem cells(SSCs). Three guides RNA (gRNAs) were designed to knockout the Stra8 gene, and knockout efficiency was evaluated in domestic chicken cells using cleavage activity of in vitro transcription of gRNA, Luciferase-SSA assay, T7 endonuclease I assay(T7E1) and TA clone sequence. In addition, the Cas9/gRNA plasmid was transfected into ESCs to confirm the function of Stra8. SSA assay results showed that luciferase activity of the vector expressing gRNA-1 and gRNA- 2 was higher than that of gRNA-3. TA clone sequencing showed that the knockdown efficiency was 25% (10/40) in DF-1 cells, the knockdown efficiency was 23% (9/40) in chicken ESCs. T7E1 assay indicated that there were cleavage activity for three individuals, and the knockdown efficiency was 12% (3/25). Cell morphology, qRT-PCR, immunostaining and FCS indicated that Cas9/gRNA not only resulted in the knockout of Stra8 gene, but also suggested that the generation of SSCs was blocked by the Stra8 gene knockdown in vitro. Taken together, our results indicate that the CRISPR/Cas9 system could mediate stable Stra8 gene knockdown in domestic chicken's cells and inhibit ECSs differentiation into SSCs.

New three-fold interpenetrated uranyl organic framework constructed by terephthalic acid and imidazole derivative.

A new 3-fold interpenetrated uranyl organic framework, UO2(bdc)(dmpi), was hydrothermally synthesized using 1,4-benzenedicarboxylic acid (H2bdc) and 1-(4-(1H-imidazol-1-yl)-2,5-dimethylphenyl)-1H-imidazole (dmpi). This framework, which was determined by synchrotron radiation X-ray, exhibited a new 3-fold interpenetrated (2,4)-connected topology with the Schläfli symbol of (12(6))(12)2. Additionally, large incurvation happened to the bond angle of [O=U=O](2+), which was always arranged in a rigorous line. Computational results based on density functional theory (DFT) indicated that the bent geometry of uranyl in UO2(bdc)(dmpi) was mainly due to the higher charge populations in the valence 6d shells of uranium, rendered by the electronegative imidazoles.

Determination of total tritium in urine from residents living in the vicinity of nuclear power plants in Qinshan, China.

To estimate the tritium doses of the residents living in the vicinity of a nuclear power plant, urine samples of 34 adults were collected from residents living near the Qinshan nuclear power plant. The tritium-in-urine (HTO plus OBT) was measured by liquid scintillation counting. The doses of tritium-in-urine from participants living at 2, 10 and 22 km were in a range of 1.26-6.73 Bq/L, 1.31-3.09 Bq/L and 2.21-3.81 Bq/L, respectively, while the average activity concentrations of participants from the three groups were 3.53 ± 1.62, 2.09 ± 0.62 and 2.97 ± 0.78 Bq/L, respectively. The personal committed effective doses for males were 2.5 ± 1.7 nSv and for females they were 2.9 ± 1.3 nSv. These results indicate that tritium concentrations in urine samples from residents living at 2 km from a nuclear power plant are significantly higher than those at 10 km. It may be the downwind direction that caused a higher dose in participants living at 22 km. All the measured doses of tritium-in-urine are in a background level range.

Radioactivity of drinking-water in the vicinity of nuclear power plants in China based on a large-scale monitoring study.

The public concern for radioactivity of drinking-water has been increasing in recent years after the rapid development of nuclear power plants, and especially after the Fukushima nuclear accident. In this study, the radioactivity of water samples collected in the vicinity of nuclear facilities from seven provinces in China was measured and an average annual equivalent effective dose derived from drinking-water ingestion was calculated. The results showed that, in winter and spring, the activities of gross α and ß ranged from 0.009 Bq/L to 0.200 Bq/L and from 0.067 Bq/L to 0.320 Bq/L, respectively. While, in summer and autumn, the activities of gross a and ß varied from 0.002 Bq/L to 0.175 Bq/L and from 0.060 Bq/L to 0.334 Bq/L. Our results indicated that the gross a and ß activities in these measured water samples were below the WHO recommended values (0.5 Bq/L for gross α and 1.0 Bq/L for gross ß) and the annual equivalent effective dose derived from drinking-water ingestion was at a safe level.

Determination of the metals by ICP-MS in wild mushrooms from Yunnan, China.

UNLABELLED: The elemental contents of Li, Cs, U, Co, As, Sr, Cd, Ba, Pb, Sb in 157 wild-grown mushrooms were determined by inductively coupled plasma mass spectrometry (ICP-MS). The mushrooms including 9 species were collected from 5 counties in Yunnan province, China. Based on the findings for the results from the certified reference materials GBW10014 (cabbage) and GBW10016 (tea), the data from the sample mushrooms were corrected. The contents of investigated trace elements in mushroom samples were determined as µg/g dry weight (dw) in the range of 0.030 to 13 for Li, 0.070 to 8.1 for Cs, 0.0010 to 0.28 for U, 0.040 to 5.4 for Co, 0.070 to 44 for As, 0.28 to 86 for Sr, and 0.15 to 23 for Cd. The maximum contents were 58, 11, and 0.11 for Ba, Pb, and Sb, respectively. The minimum contents of Ba, Pb, and Sb were below the detection limit of the method used. PRACTICAL APPLICATION: The analysis of 9 species wild-grown edible mushrooms in different regions provides the useful information to evaluate the levels of elements or of the toxic heavy metals, such as Cd, As in wild-grown edible mushrooms which grew in different regions of China for consumers and other interested groups, especially for the regulators.

Preparation of nanostructured materials by heterocoagulation-interaction of montmorillonite with synthetic hematite particles.

A nanostructured, porous material was prepared by heterocoagulation of negatively charged montmorillonite with positively charged synthetic spherical hematite particles. The process of heterocoagulation of such particles was monitored by turbidimetric titrations over the pH range 2.5-7.5. On the basis of the results of turbidimetric measurements, a series of solid materials were prepared for further characterization using ESEM, BET, XRD, and FTIR techniques. Environmental scanning electron microscopy detected isolated hematite particles or small hematite aggregates on montmorillonite surfaces (mass ratios 8:1 and 4:1). At a mass ratio of 1:1, exfoliated montmorillonite layers, covering the hematite particles as semi-transparent blankets were seen. A low mass ratio led to compact hematite particle aggregates covering the montmorillonite surfaces. Nitrogen-gas-adsorption isotherms revealed the sorption properties to be gradually dependent upon mass ratios. Pore volume distributions showed that mesopores with diameter of about 10-20 nm were produced in the heterocoagulates with mass ratios of 4:1, 1:1, and 1:8. The sample prepared with a 4:1 mass ratio showed the greatest BET surface area, which decreased slightly upon sample calcination at 500 degrees C. X-ray diffraction measurements were used to investigate layer stacking, by comparing the integral intensities of d(001) reflection. For this purpose, samples with 4:1 mass ratios, prepared both by heterocoagulation and mechanical grinding, were used. It was found that heterocoagulation effectively diminished the stacking of the layers to about 85%; hence, a significant amount of fundamental, 1 nm thick montmorillonite layers was achieved in this sample.