Search

This study was carried out to evaluate the contribution of different types of iron-organic matter associations (Fe-OM) to the phosphorus sorption capacity of peatland. Humic substance (HS) and particulate organic matter (POM) were isolated from peat soils, and different types of iron-organic matter associations (Fe-HS and Fe-POM) were prepared. Then, isothermal adsorption experiments were carried out on the synthesized Fe-OM and iron-contained peat soils. The morphology structure of Fe-HS associations is amorphous like that of ferrihydrite. The theoretical maximum adsorption capacity (Q

Maize (Zea mays) is one of the most important staple food and primary source of livestock feed in the world. As the consumption of maize grown on the selenium-enriched soils of Naore Valley is one of the apparent causes of selenosis in the area, this work collected and analyzed total Se, Se fractions, and Se species distributions in maize plant samples, including grains, leaves, stalks, roots, rhizosphere soils, and the most representative parent rock materials from Naore Valley, Ziyang County, China. The Se distribution in soils markedly correlated with the weathered Se-enriched bedrocks, but most of the Se in the analyzed soils is enclosed as recalcitrant residual Se and organic-sulfide bound Se. In contrast, Se in rocks had a comparatively higher bioavailability and is bounded mainly to organic matter and sulfides minerals, with very few of the Se enclosed in the residual fraction. Maize plants might take a large amount of Se from the organic-sulfide bound Se fraction in the Se-rich soils, the weathered products from bedrocks or plant litters. Total Se concentrations in the collected samples were observed in descending order soil>leaf>root>grain>stalk. The predominant Se species detected in maize plants was SeMet. Se inorganic forms, mainly Se(VI), decreased from root to grain and were possibly assimilated into organic forms. Se (IV) was barely present. The natural increases in Se concentration affected mainly leaf and root dry-weight biomass as they are the organs that coped with the highest Se accumulation. This paper offers an insight into the uptake, accumulation, and distribution of Se forms in natural Se-rich maize crops and an opportunity for shifting Se-rich soils from menaces to valuable resources for growing Se-rich agricultural products.

Background:The standard approach for treating patients with paroxysmal supraventricular tachycardia(PSVT) is radiofrequency ablation. In patients with PSVT difffculty in ablation of accessory pathways(APs) is associated with failures and recurrences. Existence of epicardial and endocardial AP is a special case resulting in difffculties in radiofrequency ablation. Case presentation: A 54-year-old female had a symptom of recurrent palpitation for 40 years. The electrocardiogram(ECG) showed supraventricular tachycardia. As the tachycardic episodes had been poorly controlled with conservative treatment, the patient underwent radiofrequency ablation. Invasive electrophysiology study performed and confirmed that the rare occurrence of both endocardial and epicardial AP in this case. The accessory pathways were epicardial AP of mitral valve annulus and endocardial AP of tricuspid annulus and mitral annulus posterior septum. Both epicardial and endocardial AP in one case was rare, however, ablation of this challenging and rare case is successful.The patient's ECG was normal after operation.. During the follow-up, the patient has had no recurrent tachycardia. Conclusions: This rare and challenging case offers evidence for viable technique of epicardial ablation when conventional endocardial ablation process fail to block the AP conduction. As in this case, repeat strategy of electrophysiological study and precise mapping by an experienced operator should be a prerequisite to attempt ablation treatment.

Selenium (Se), iron (Fe), and humic acid (HA) are beneficial fertilizers that inhibit cadmium (Cd) uptake in crops and are crucial for agricultural yields as well as human health. However, the joined effect of Se, Fe, and HA on Cd uptake in rice are still poorly understood. Therefore, a hydroponic culture experiment was established to evaluate the combined effect of Se (Se4+ or Se6+), Fe, and HA on the biomass, Cd uptake, and Cd translocation of/in rice seedlings. Compared to Se6+ application, Se4+ application in most treatments resulted in lower Cd translocations from roots to shoots, leading to a significant decrease in shoot Cd concentrations. Compared to the treatments with Se4+ or Fe2+ application, joined application of Se4+ and Fe2+ inhibited Cd uptake in shoots by decreasing Cd adsorption onto (iron plaque) and uptake by roots, and alleviating Cd translocation from root to shoot. Compared to the treatments with Se6+ or Fe2+ application, joined application of Se6+ and Fe2+ inhibited Cd uptake in shoots by sequestering (retaining) Cd onto root surface (iron plaque). HA inhibited Cd uptake in all treatments by decreasing the bioavailability of Cd in the nutrient solution through complexation. The simultaneous application of Se, Fe, and HA decreased the shoot Cd concentrations the most, followed by the combined application of two fertilizers and their individual application; the mean shoot Cd concentration in the Fe-SeIV-HA2 treatment was the lowest among all the treatments, at only 11.39 % of those in the control treatments. The 3-way ANOVA results indicated that the Cd concentrations in shoots were significantly affected by Se, Fe, HA, and certain of their interactions (Fe×Se and Se×HA) (p< 0.05). The above findings suggest that the joined application of Se, Fe, and HA ameliorated Cd uptake mainly by inhibiting Cd adsorption onto (iron plaque) and uptake by roots and the translocation from roots to shoots (Fe×Se4+), retaining (sequestering) Cd in iron plaque (Fe×Se6+), and decreasing Cd availability in nutrient solution (HA).

Selenium (Se) enrichments or deficiency in maize (Zea mays L.), one of the world’s most important staple foods and livestock feeds, can significantly affect many people’s diets, as Se is essential though harmful in excess. In particular, Se-rich maize seems to have been one of the factors that led to an outbreak of selenosis in the 1980s in Naore Valley in Ziyang County, China. Thus, this region’s geological and pedological enrichment offers some insight into the behavior of Se in naturally Se-rich crops. This study examined total Se and Se species in the grains, leaves, stalks, and roots of 11 maize plant samples, Se fractions of soils around the rhizosphere, and representative parent rock materials from Naore Valley. The results showed that total Se concentrations in the collected samples were observed in descending order of soil > leaf > root > grain > stalk. The predominant Se species detected in maize plants was SeMet. Inorganic Se forms, mainly Se(VI), decreased from root to grain, and were possibly assimilated into organic forms. Se(IV) was barely present. The natural increases of Se concentration in soils mainly affected leaf and root dry-weight biomasses of maize. In addition, Se distribution in soils markedly correlated with the weathered Se-rich bedrocks. The analyzed soils had lower Se bioavailability than rocks, with Se accumulated predominantly as recalcitrant residual Se. Thus, the maize plants grown in these natural Se-rich soils may uptake Se mainly from the oxidation and leaching of the remaining organic-sulfide-bound Se fractions. A viewpoint shift from natural Se-rich soils as menaces to possibilities for growing Se-rich agricultural products is also discussed in this study.

This study was carried out to evaluate the efficiency and mechanism of P removal by different types of Fe-OM associations in peatlands. Humic substance (HS) and particulate organic matter (POM) were isolated from peat soils, and different types of iron-organic matter associations (Fe-HS and Fe-POM) were prepared. In addition, the natural combination of Fe3+ with peat was simulated. Then, isothermal adsorption experiments were carried out on the synthesized Fe-OM and iron-contained peat soils. All the adsorption data can be well fitted by the Langmuir adsorption model. The theoretical maximum adsorption capacity (Qmax) of Fe-HS associations can reach 36.90 mg/g, which is approximately two times higher than that of ferrihydrite (19.23 mg/g) and ten times higher than that of hematite (3.26 mg/g) and goethite (2.08 mg/g). The adsorption capacities of peat soils and POM were significantly enhanced by combinations with exogenous Fe3+. The Qmax of the original peat and iron-contained peat were 2.83 mg/g and 7.36 mg/g, respectively, and those of the original POM and Fe-POM association were 4.31 mg/g and 5.89 mg/g, respectively. The contribution of Fe-OM associations to phosphorus removal in peatlands is much higher than that of inorganic iron oxide. In addition, exogenous Fe3+ could also participate in other phosphorus removal processes.

Dietary intake of selenium (Se)-enriched rice has benefit for avoiding Se-deficient disease, but there is a risk of excessive cadmium (Cd) intake. Through hydroponic culture and adsorption-desorption experiments, this paper focused on Se and Cd uptake in rice seedlings associated with the interactive effects of Se (Se

The objectives of this study were to evaluate the cadmium adsorption capacity of iron–organic associations (Fe-OM) formed by laccase-mediated modification and assess the effect of Fe-OM on the immobilization of cadmium in paddy soil. Leaf organic matter (OM) was extracted from Changshan grapefruit leaves, and then dissolved organic matter (Lac-OM) and precipitated organic matter (Lac-P) were obtained by laccase catalytic modification. Different Fe-OM associations were obtained by co-precipitation of Fe with OM, Lac-OM, and Lac-P, respectively, and the adsorption kinetics, adsorption edge, and isothermal adsorption experiments of Cd on Fe-OM were carried out. Based on the in situ generation of Fe-OM, passivation experiments on Cd-contaminated soils with a high geological background were carried out. All types of Fe-OM have a better Cd adsorption capacity than ferrihydrite (FH). The theoretical maximum adsorption capacity of the OM-FH, Lac-OM-FH, and Lac-P-FH were 2.2, 2.53, and 2.98 times higher than that of FH, respectively. The adsorption of Cd on Fe-OM is mainly chemisorption, and the -OH moieties on the Fe-OM surface form an inner-sphere complex with the Cd ions. Lac-OM-FH showed a higher Cd adsorption capacity than OM-FH, which is related to the formation of more oxygen-containing groups in the organic matter modified by laccase. The immobilization effect of Lac-OM-FH on active Cd in soil was also higher than that of OM-FH. The Lac-OM-FH formed by laccase-mediated modification has better Cd adsorption performance, which can effectively inactivate the activity of Cd in paddy soil.

Background In accessory pathway-related supraventricular tachycardia ablation, coronary sinus (CS) ablation has received more and more attention, but there are no accurate criteria for catheter selection. Objectives We intended to develop a new method for the reasonable selection of electrode for coronary sinus ablation via assessing the relationship between the accessory pathway (AP) potential and time of successful ablation. Methods Among the patients who had detected the bypass potential during radiofre-quency ablation between 1/1/2015 and 12/31/2019, 30 patients underwent radiofrequency catheter ablation (RFCA) in CS. The relationship between AP potential and time of successful ablation was analyzed. Results In CS ablation, the median baseline amplitude of the AP potentials in patients with successful Temperature control catheter (TCC) ablation was higher than that in patients with Irrigated-tip catheter (ITC) following TCC ablation failure (p = 0.02). The optimal cutoff value of the amplitude of the AP potential to guide the selection of a catheter for ablation was 1.07 mV, and the sensitivity and specificity were 80% and 90%, respectively. Conclusions The AP potential is helpful for the electrode selection in CS ablation.

The association of organic matter with iron (Fe-OM associations) is recognized as an important stabilization mechanism for soil organic matter. Our objective was to assess the factors regulating stabilization of soil organic matter by iron in various plant-dominated peatlands, and the role of laccase in the formation of Fe-OM associations. We investigated Fe-bound OC content and related physicochemical and biochemical parameters in four plots with different successional vegetation, and a set of simulations was conducted to investigate the association of Fe and peat-derived dissolved organic carbon catalysed by laccase. Our results indicate Fe-bound OC content varies regularly with the succession gradients, and a significant positive relationship between laccase activities and Fe-bound OC content was found (R = 0.77, P

Natural organic acids, such as humic acid (HA), play crucial roles in biogeochemistry of anions and cations in soil due to their numerous functional groups on their surfaces. Selenium (Se) and cadmium (Cd) could bind strongly to HA; nevertheless, it is still unclear as to the effects of HA on Se and Cd uptake in rice which will be focused on in this paper. Pot experiments were carried out at Huazhong Agricultural University, Wuhan City, Hubei Province, China. Agricultural soils were treated with different concentrations of HA (0, 4, and 8 g kg−1 soil) and Se (SeIV or SeVI) (0 and 2 mg kg−1 soil) as well as with base fertilizer 3 days prior to planting. For Cd treatment, experimental soils were treated with Cd (0 and 2 mg kg−1 soil) 1 month before sowing. For element determination, root (after DCB extraction) and shoot samples were digested with a mixed solution of HNO3-HClO4, and the Se and Cd in digest solution were measured by HG-AFS and ICP-MS, respectively. Fe, Se, and Cd in iron plaque were extracted by DCB extraction and measured by AAS, HG-AFS, and ICP-MS, respectively. HA reduced Se (or Cd)-induced growth stimulation and Se and Cd uptake in rice seedlings, whereas iron plaque formation varied little with different treatments. HA inhibited SeIV (or SeVI) uptake in rice seedlings by reducing Se translocations from soil to iron plaque (or by increasing Se adsorption capacity of iron plaque and decreasing Se transport from iron plaque to root). HA reduced Cd uptake in rice seedlings by reducing Cd transport from soil to iron plaque and from iron plaque to root. Compared with single addition of SeIV or SeVI or HA, adding HA combined with SeIV or SeVI could further reduce Cd uptake in rice seedlings, whereas Se contents of aerial tissues did not change obviously. HA inhibited the accumulation of Se (SeIV or SeVI) and Cd in rice seedlings; nevertheless, the mechanism was different. Compared with adding Se (or HA) alone, application of Se mixed with HA might be a more effective way to produce Se-enriched and Cd-deficient crop in Cd-contaminated soil.

Shale gas resources have been regarded as a viable energy source, and it is of great significance to characterize the shale composition of different cements, such as quartz and dolomite. In this research, chemical analysis and the multifractal method have been used to study the mineral compositions and petrophysical structures of cements in shale samples from the Longmaxi Formation, China. X-ray diffraction, electron microprobe, field emission scanning electron microscopy, cathodoluminescence microscopy and C-O isotope analyses confirmed that cements in the Longmaxi Formation shales are mainly composed of Fe-bearing dolomite and quartz. Fe-bearing dolomite cements concentrate around dolomite as annuli, filling micron-sized inorganic primary pores. Quartz cements in the form of nanoparicles fill primary inter-crystalline pores among clay minerals. Theoretical calculation shows that the Fe-bearing dolomite cements formed slightly earlier than the quartz cements, but both were related to diagenetic illitization of smectite. Moreover, multifractal analysis reveals that the quartz cements are more irregularly distributed in pores than the Fe-bearing dolomite cements. These results suggest that the plugging effect of the quartz cements on the primary inoraganic pore structures is the dominant factor resulting in low interconnected porosity of shales, which are unfavorable for the enrichment of shale gas.

Currently, the challenges of oil/gas target prospecting by surface soil geochemical exploration are the covers of the prospecting regions. And the arid, sandy, undeveloped deserts of Xinjiang, China, are merely the geographic challenges facing today's oil and gas exploration and production industry. While there is too often much complex information to assimilate and understand for quick and accurate decisions leading to improved reservoir management, advanced technology, such as the development of newer algorithms and numerical methods that can be helpful in exploration to process large and/or old geochemical datasets to improve targeting of buried oil/gas geochemical systems. Herein, we investigated the possibility that geochemical concentration distribution in space may be members of a special class of complex processes, termed as multifractal, which require a large number of exponents to characterize their scaling properties. In addition, the results present that the 15 petroleum indices of study could be classified into three groups according to their multifractal spectra. The three groups of the indices are discriminated well by several multifractal parameters. Such discrimination results are in agreement well with the analytical results by statistical cluster analysis results and principal component analysis method (PCA) included in the software package of GeoDAS. Based on the PCA results, C-A (concentration-area) fractal method has been applied in this paper to delineate the geochemical anomaly areas for petroleum resources prediction. The first and second components clearly represent the potential petroleum prospecting areas which correspond well to the discovered oil/petroleum sites. Both the multifractal method and spatial analysis technique in this paper provide new insights into the selection of target indices of petroleum geochemical exploration as well as comprehensive information extraction for oil/gas target prospecting by surface soil geochemical exploration.

Selenium (Se), iron (Fe), and humic acid (HA) are beneficial fertilizers that inhibit cadmium (Cd) uptake in crops and are crucial for agricultural yields as well as human health. However, the joined effect of Se, Fe, and HA on Cd uptake in rice are still poorly understood. Therefore, a hydroponic culture experiment was established to evaluate the combined effect of Se (Se

Background: The ablation of the coronary sinus (CS) is becoming more and more important in accessory pathway-related supraventricular tachycardia ablation. In comparison with temperature-controlled catheters (TCC), irrigated-tip catheter (ITC) are more expensive and cause more damage in accessory pathway-related supraventricular tachycardia ablation. We intended to develop a new method for the reasonable selection of electrode for coronary sinus(CS) ablation via assessing the relationship between the accessory pathway (AP) potential and time of successful ablation. Methods：Among the patients who had detected the bypass potential during radiofrequency ablation between 1/1/2015 and 12/31/2019. TCC was performed in 330 patients receiving endocardial ablation. 30 patients underwent radiofrequency catheter ablation (RFCA) in CS. The relationship between AP potential and time of successful ablation was analyzed. Results：330 cases of TCC ablation within the endocardium revealed that the amplitude of AP potential was significantly and negatively correlated with the time of successful ablation (r = -0.79, p < 0.001). In CS ablation, the median baseline amplitude of the AP potentials in patients with successful TCC ablation was higher than that in patients with ITC following TCC ablation failure (p = 0.02). The optimal cutoff value of the amplitude of the AP potential to guide the selection of a catheter for ablation was 1.07 mV, and the sensitivity and specificity were 80% and 90%, respectively. Conclusion：The AP potential is helpful for the electrode selection in CS ablation.

Carbon fibers (CF) have triggered extensive interest with the progress of multifarious marine electric field sensor devices owing largely to their high flexibility, good conductivity and exceptional chemical/thermal stability. Herein, flexible Ag/sliver nanowires (AgNWs)/CF (Ag-AgNWs-CF) electrodes with extremely tiny potential difference drift of 67.22 μV/24 h have been successfully fabricated by a facile alcohol-thermal method with a reaction temperature of 170℃ for 120 min. The conductive AgNWs was introduced to the CF as a coating material. The AgNWs with three-dimensional (3D) network and silver particles accounts for superior areal specific capacitance and low Tafel slope for the composite electrodes (CEs). Using such flexible Ag-AgNWs-CF as a marine electric field sensor, the excellent self-noise was obtained, which signifies prospective ability to respond to weak signals.

Porcine astrovirus (PAstV), associated with mild diarrhea and neurological disease, is transmitted in pig farms worldwide. The purpose of this study is to elucidate the main factors affecting codon usage to PAstVs. Phylogenetic analysis showed that the subtype PAstV-5 sat at the bottom of phylogenetic tree, followed by PAstV-3, PAstV-1, PAstV-2, and PAstV-4, indicating that the five existing subtypes (PAstV1-PAstV5) may be formed by multiple differentiations of PAstV ancestors. A codon usage bias was found in the PAstVs-2,3,4,5 from the analyses of effective number of codons (ENC) and relative synonymous codon usage (RSCU). Nucleotides A/U are more frequently used than nucleotides C/G in the genome CDSs of the PAstVs-3,4,5. Codon usage patterns of PAstV-5 are dominated by mutation pressure and natural selection, while natural selection is the main evolutionary force that affects the codon usage pattern of PAstVs-2,3,4. The analyses of codon adaptation index (CAI), relative codon deoptimization index (RCDI), and similarity index (SiD) showed the codon usage similarities between the PAstV and animals might contribute to the broad host range and the cross-species transmission of astrovirus. Our results provide insight into understanding the PAstV evolution and codon usage patterns.

Evaluating the bioaccumulation and health risk of heavy metals in soil-crop systems is essential in Liujiang karst regions. In the current study, the single and comprehensive uptake effects of heavy metals (i.e., Cu, Cr, Cd, As, and Zn) between rice and sugarcane and their rhizosphere soils were investigated. The estimated daily ingestion (EDI), target hazard quotient (THQ), and hazard index (HI) were estimated for health risk assessments. The results showed that the mean contents of Cu, Cr, Cd, As, and Zn in rice soils were 25.8, 168, 1.91, 20.0, and 160 mg/kg, respectively, and those in sugarcane soils were 28.8, 186, 0.44, 31.0, and 108 mg/kg. Rice soils were mainly contaminated by Cd, and Cd and Cr were the main pollutants in sugarcane soils. The average concentrations of Cu, Cr, Cd, As, and Zn in rice grains were 1.79, 0.15, 0.16, 0.11, and 12.7 mg/kg, respectively, and in sugarcanes were 0.10, 0.036, 0.022, 0.006, and 0.38 mg/kg. Both crops tended to take up Cd more effectively, and rice grains exhibited higher accumulation capacities of heavy metals in edible part than sugarcanes. Prediction models of Cd and comprehensive accumulation factors were established for rice and sugarcane, and different soil factors affect metal accumulation in crops cultivated in different types. Due to the exposure to As and Cd through rice consumption, non-carcinogenic risks are likely to occur in Liujiang residents.

Ge and Si differ strongly in their biogeochemical behavior due to the differences in binding capacity to organic matter. The mechanisms of soil organic matter affecting the mobility and bioavailability of Ge in soil-plant system remain unclear. This work aimed to investigate the soil Ge fractions and Ge binding to humic substances in paddy soil. Paddy soil samples taken from Changxing County, Zhejiang Province, China, were investigated by the sequential extraction method. Humic acid (HA) and fulvic acid (FA) isolated from paddy soils were characterized by Fourier transform infrared spectrometry (FT-IR) and 3-dimensional excitation-emission matrix (3D-EEM). The effect of humic substances on the binding of Ge was studied by fluorescence-quenching titration. Results showed that residual Ge was the dominant fraction in soil (up to 85%). The mobile Ge, organic matter bound Ge and easily reduceable compounds bound Ge accounted for approximately 10% of soil TGe and may represented critical labile pools of soil Ge. Organic matter bound Ge significantly correlated (r = 0.56, p

Phenolics from peatlands have been proven to enhance the solubility of iron, even under alkali or saline conditions, by forming iron-phenolic complexes. However, the photo-stability of these complexes has received little attention thus far. Based on the investigation of water and peat samples in Jinchuan peatland, in northern China, simulated experiments – using Gallic acid (GA) as a structural analog of peat-derived phenolic acid – were carried out to clarify the mechanisms of photo-stability of iron-phenolic complexes. Our research confirmed that when the molar ratio of GA to Fe reaches 0.1:1, photolysis led to some Fe deposition. By comparing GA concentrations under aerobic/anaerobic conditions, we demonstrated that dissolved oxygen plays a key role, not only in GA autoxidation but also in photo-degradation of GA through direct and indirect photolysis. Besides, adding coexisting phenolic acids into GA/iron systems showed various effects, depending on the different functional groups, while the dominant species of phenolic acids in peatlands, such as p-cumaric acid and p-hydroxybenzoic acid, may still act as reactive oxygen species scavengers, protecting over 99% of the dissolved iron under solar irradiation. Our results indicate that by forming iron-organic complexes with certain phenolics from peatlands, dissolved iron can be effectively protected from precipitation during freshwater transport under solar irradiation, which has profound implications for controlling the limited primary production in certain marine areas.

Cadmium contamination in rice has become an increasing concern in many countries including China. A simple, cost-effective, and highly sensitive method was developed for the determination of trace cadmium in rice samples based on a new high-efficient liquid spray dielectric barrier discharge induced plasma (LSDBD) vapor generation coupled with atomic fluorescence spectrometry (AFS). The analytical procedure involves the efficient formation of Cd volatile species by LSDBD plasma induced chemical processes without the use of any reducing reagents (Na/KBH4 in conventional hydride generation). The effects of the addition of organic substances, different discharge parameters such as discharge voltage and discharge gap, as well as the foreign ion interferences were investigated. Under optimized conditions, a detection limit of 0.01 μg L− 1 and a precision of 0.8% (RSD, n = 5, 1 μg L− 1 Cd) was readily achieved. The calibration curve was linear in the range between 0.1 and 10 μg L− 1, with a correlation coefficient of R2 = 0.9995. Compared with the conventional acid-BH4− vapor generation, the proposed method not only eliminates the use of unstable and expensive reagents, but also offers high tolerance for coexisting ions, which is well suited to the direct analysis of environmental samples. The validation of the proposed method was demonstrated by the analysis of Cd in reference material of rice (GBW080684). It was also successfully applied to the determination of trace cadmium in locally collected 11 rice samples, and the obtained Cd concentrations are ranged from 7.2 to 517.7 μg kg− 1.

The spatial and temporal variability, effects, and mechanisms of the Indian Summer Monsoon (ISM) have been investigated intensively during the past few decades. The pattern of a relatively strong ISM during the early to middle Holocene, and a relatively weak ISM in the late Holocene, has been widely demonstrated in both marine and continental records. However, the timing of the ISM onset during the early Holocene remains controversial. Here, we present oxygen isotope record from ostracods and hydrogen isotope record from sedimentary leaf waxes from a sediment core at Linggo Co, a glacier-fed lake on the central Tibetan Plateau, in order to investigate the onset of the ISM. The ostracod δ18O record indicates an early ISM onset at ~11.7 ka, whereas the leaf wax δD record indicates a later ISM onset at ~10 ka. This apparent two-step development of the ISM revealed by aquatic and terrestrial records is confirmed by principal component analysis of nine marine records from the ISM domain. The comparison between isotope records from Linggo Co and the marine records implies that the early ISM onset was likely linked to elevated temperatures in the Northern Hemisphere, while the later ISM onset may be related to intensified precipitation.

The efficacy of pulmonary vein antral isolation for patients with prolonged sinus pauses (PSP) on termination of atrial fibrillation has been reported. We studied the right atrial (RA) electrophysiologic and electroanatomic characteristics in such patients. Forty patients underwent electroanatomic mapping of the RA: 13 had PSP (group A), 13 had no PSP (group B), and 14 had paroxysmal supraventricular tachycardia (control group C). Group A had longer P-wave durations in lead II than did groups B and C (115.5 ± 15.4 vs 99.5 ± 10.9 vs 96.5 ± 10.4 ms; P=0.001), and RA activation times (106.8 ± 13.8 vs 99 ± 8.7 vs 94.5 ± 9.1 s; P=0.02). Group A's PP intervals were longer during adenosine triphosphate testing before ablation (4.6 ± 2.3 vs 1.7 ± 0.6 vs 1.5 ± 1 s; P We found that patients with PSP upon termination of atrial fibrillation have RA electrophysiologic and electroanatomic abnormalities that warrant post-ablation monitoring.

The mid-latitude westerlies and Indian summer monsoon (ISM) have a significant impact on the water budget and general environment of the Tibetan Plateau (TP), and much work has been conducted in order to characterize variations in these two atmospheric circulation systems on various time scales. However, the nature of the interplay between the Asian summer monsoon and the westerlies during the last deglaciation remains controversial. In this study, a sediment core from Linggo Co, a closed lake in the central TP, was analyzed for grain size and ostracod content. The results suggest that environmental change in the Linggo Co basin during the past 17 ka can be divided into four stages: during Stage 1 (17–11.7 ka) Linggo Co was a shallow lake characterized by high amplitude hydrological fluctuations. Strong winds prevailed in winter, correlative with cold events in the North Atlantic region, and indicating the dominance of the westerlies. During Stage 2 (~11.7 ka), in the early Holocene, Linggo Co expanded rapidly and there was the disappearance of the shallow-water ostracod species Limnocythere inopinata together with a decrease in mean grain-size. These changes indicate that ISM was enhanced and that it was the dominant atmospheric circulation affecting TP rather than the westerlies. During Stage 3 (10–8 ka) Linggo Co experienced several intervals with a negative water budget, which may be attributed to a weakening of the weaken ISM or to the reduced influx of glacial meltwater as a result of the influence of cold climatic events. During Stage 4, after 8 ka, Linggo Co shrank progressively in parallel with a gradual weakening of the ISM and finally a transition to the present environment occurred at ~2.5 ka. A comparison of the record from Linggo Co and other records from the TP reveals that prior to 16.5 ka the mid-latitude westerlies was the dominant atmospheric circulation system controlling the entire TP. From 16.5 to 11.5 ka, the mid-latitude westerlies still controlled the central-northern TP; however, the ISM controlled the southern TP, which had a similar climatic pattern to the present day. During the early-middle Holocene, the ISM was the dominant system affecting the entire TP; however, its influence was considerably reduced during the late Holocene, which was probably accompanied by a strengthening of the westerlies.

Ziyang County, Shaanxi Province, China is a world known selenium (Se)-enriched area, and a severe selenosis incident was reported in Naore Village during the 1990s. This study investigated the geochemical characteristics of Se and its fractions in Se-enriched rocks from Ziyang. Se distribution is uneven, ranging from 0.23 to 57.00 μg/g (17.29±15.52 μg/g). Se content is higher in slate than chert, and even lower in carbonate rocks. Cd, As and V are enriched but Pb is depleted in Se-enriched strata. Se has different correlations both with TS (total sulfur) (R 2=0.59 for chert) and TC (total carbon) (R 2=0.77 for slate, R 2=0.87 for carbonate). Se has significant positive correlations with V (r=0.65), As (r=0.485), Cd (r=0.459) and Pb (r=0.405). The Se level correlates with mineral content, positively with pyrite, chlorite and illite, negatively with albite. Se associated with sulfide/selenide and elemental Se are the predominant fractions of total recovered Se, suggesting that a reducing environment and the formation of sulfides were significant to Se deposition during its geochemical cycle. Although low concentration of bio-available Se (average 5.62%±3.69%) may reduce the risk of Se poisoning in the target area, utilization of Se-rich rock as natural fertilizer should be restricted.

Fertilizing soil with selenium (Se)-enriched slate could increase Se levels in crops; however, this process is limited by the low Se bioavailability of Se-enriched slate. In this work, a calcination procedure for Se-enriched slate using CaO as a sorbent was developed, and the process significantly improved the bioavailability of Se. The calcination experiments were conducted with the calcium (Ca)-based sorbents CaO or CaCO 3 at 300–800 °C. Most of the Se in the organic matter and sulfides were emitted between 400 and 650 °C, and CaO exhibited a higher adsorption efficiency of Se compared with CaCO 3 . The optimum temperature was 600 °C as determined by the high contents of bioavailable Se (10 times that of the original slate) and Se(VI) in the calcinated samples with the sorbent CaO. Both the physical adsorption of CaO and the formation of CaSeO 3 contributed to the conversion of Se associated with organic matter and sulfide minerals to bioavailable Se species. The transformation of Se(IV) to Se(VI) might have been caused by the co-oxidation of O 2 and the generation of HCl during the calcination process. The Se concentrations in potatoes amended with activated slate reached 650 ± 23 μg/kg, which verified the high Se bioavailability of the calcinated product. The proposed calcination procedure could support the exploitation of Se-enriched slate and the preparation of Se soil amendments.

BACKGROUND An increasing number of patients with chronic heart failure (CHF) are demanding more convenient and efficient modern health care systems, especially in remote areas away from central cities. Telehealth is receiving increasing attention, which may be useful to patients with CHF. OBJECTIVE This study aimed to evaluate the feasibility of a hospital-community-family (HCF)–based telehealth program, which was designed to implement remote hierarchical management in patients with CHF. METHODS This was a single-arm prospective study in which 70 patients with CHF participated in the HCF-based telehealth program for remote intervention for at least 4 months. The participants were recruited from the clinic and educated on the use of smart health tracking devices and mobile apps to collect and manually upload comprehensive data elements related to the risk of CHF self-care management. They were also instructed on how to use the remote platform and mobile app to send text messages, check notifications, and open video channels. The general practitioners viewed the index of each participant on the mobile app and provided primary care periodically, and cardiologists in the regional central hospital offered remote guidance, if necessary. The assessed outcomes included accomplishments of the program, usability and satisfaction, engagement with the intervention, and changes of heart failure–related health behaviors. RESULTS As of February 2018, a total of 66 individuals, aged 40-79 years, completed the 4-month study. Throughout the study period, 294 electronic medical records were formed on the remote monitoring service platform. In addition, a total of 89 remote consultations and 196 remote ward rounds were conducted. Participants indicated that they were generally satisfied with the intervention for its ease of use and usefulness. More than 91% (21/23) of physicians believed the program was effective, and 87% (20/23) of physicians stated that their professional knowledge could always be refreshed and enhanced through a library hosted on the platform and remote consultation. More than 60% (40/66) of participants showed good adherence to the care plan in the study period, and 79% (52/66) of patients maintained a consistent pattern of reporting and viewing their data over the course of the 4-month follow-up period. The program showed a positive effect on self-management for patients (healthy diet: P=.046, more fruit and vegetable intake: P=.02, weight monitoring: P=.002, blood pressure: PP=.049, and daily dosages of medicine taken: P=.006). CONCLUSIONS The HCF-based telehealth program is feasible and provided researchers with evidence of remote hierarchical management for patients with CHF, which can enhance participants’ and their families’ access and motivation to engage in self-management. Further prospective studies with a larger sample size are necessary to confirm the program’s effectiveness.

A highly efficient liquid spray dielectric barrier discharge (LSDBD) plasma-induced vapor generation technique is developed for the simultaneous determination of selenium, silver, antimony, lead, and bismuth in liquid microsamples (20 μL) by inductively coupled plasma mass spectrometry (ICP-MS). It is demonstrated that the dissolved Se, Ag, Sb, Pb, and Bi ions in solution samples are readily and simultaneously converted to volatile species efficiently by LSDBD plasma-induced chemical processes under similar conditions. It eliminates the use of unstable and expensive reducing reagents, and only formic acid is required in the proposed LSDBD chemical vapor generation technique. It is also worth noting that this is the first report of using plasma-induced chemical processes for the vapor generation of Ag and Bi. The simultaneous sensitive determination of Se, Ag, Sb, Pb, and Bi is realized with a sample volume of only 20 μL and the sample throughput could be as high as 180 samples h–1. The limit of detection ...

Since the environmental pollution is becoming more and more serious, TiO2 nanotube arrays, as a new kind of photocatalytic degradation materials have been widely researched and applied in our society. In order to enhance its photocatalytic performance, TiO2 nanotube arrays modified by La2O3 were successfully synthesized via an anodic oxidation method through dissolved La2O3 powder in the organic electrolyte. The photoelectron chemical performances of the composite nanotube arrays were characterized by FE-SEM, XRD, UV, and the photocatalytic activity was evaluated by photodegrading methylene blue which was treated as the target pollutants. The analytical results demonstrated that the La2O3 modified TiO2 nanotube arrays has a more significantly increased capability for photocatalytic properties than the pure TiO2 nanotube arrays, and the new concept was helpful to guide the synthesis of robust visible-light photocatalysts.

Pyrite-bearing volcanic tuff and carbonaceous slates of the Lower Cambrian Lujiaping Formation have been considered the source of selenium (Se) in high-Se soils in the area of the Naore Village of the Ziyang County, China, where acute Se toxicity occurred in the 1980s. For geochemical exploration, the accumulation and distribution of Se and trace elements within the pyrite grains are of great indicative significance for understanding the possible origin and forming mechanism of the Se enrichment. In this work, 7 rock samples and 89 pyrite grains were collected and analysed to investigate the element micro-distribution within the pyrite grains using EPMA and LA-ICP-MS. The whole-rock analysis shows that the pyrite-bearing Lower Cambrian rocks in Ziyang are commonly enriched in Se, As, Mo, Cd, Cr, Ni, Sb, Cu and Ba. In situ microanalysis indicates that Se (30–1880 μg/g) and As (160–2960 μg/g) concentrations within the pyrite grains are 1–2 orders of magnitude higher than those in the host rocks (Se: 0.56–73.1 μg/g, As: 2.56–195 μg/g) and that the Se contents are negatively correlated with pyrite mineral sizes. Grain-scale element mappings of fresh Se-enriched pyrites reveal two types of Se and As distribution patterns (type-I: high-Se 120–1870 μg/g and low-As

International audience; Together with generalized self-similarity and the fractal spectrum, local singularity analysis has been introduced as one part of the new 3S principle and technique for mineral resource assessment based on multifractal modeling, which has been demonstrated to be useful for anomaly delineation. Local singularity is used in this paper to characterize the property of multifractal distribution patterns of geochemical indexes to delineate potential areas for oil/gas exploration using the advanced GeoDAS GIS technology. Geochemical data of four oil/gas indexes, consisting of acid-extracted methane (SC1), ethane (SC2), propane (SC3), and secondary carbonate (?C), from 9637 soil samples amassed within a large area of 11.2×104 km2 in the Songpan-Aba district, Sichuan Province, southwestern China, were analyzed. By eliminating the interference of geochemical oil/gas data with the method of media-modification and Kriging, the prospecting area defined by the local singularity model is better identified and the results show that the subareas with higher singularity exponents for the four oil/gas indexes are potential targets for oil/gas exploration. These areas in the shape of rings or half-rings are spatially associated with the location of the known producing drilling well in this area. The spatial relationship between the anomalies delineated by oil/gas geochemical data and distribution patterns of local singularity exponents is confirmed by using the stable isotope of ?13C.

Hydrothermal mineralization can cause enrichment or depletion of elements in ore bodies and surrounding country rocks. Local metal-enriched rocks can become an ore body that can be mined at an economic profit. Therefore, understanding the spatial distribution of elements caused by mineralization is crucial for mineral exploration and resource assessment. In this study, a total of 24 representative samples were collected from different veins within the Tongchang ore body of the Dexing porphyry Cu–Mo Deposit. The objectives of this work were firstly to identify different vein types and secondly to evaluate the potential of multifractal parameters, constructed using the so-called method of moments, to characterize the spatial and temporal distribution patterns of concentration of elements on mineral surfaces, which may provide insight into hydrothermal mineralization and its effect on spatial and temporal distribution of element concentration. Based on the analytical results and previous investigations, the vein systems within the deposit can be divided into four main types as follows: (1) early quartz veins (A-type veins) related to K-feldspar alteration; (2) quartz-pyrite-molybdenite-chalcopyrite veins (B-type veins) related to chlorite+illite alteration; (3) quartz-pyrite-chalcopyrite veins (D-type veins) related to late phyllic (muscovite+quartz) alteration; and (4) the latest carbonate-sulphate-oxide veins (H-type veins). The multifractal distributions of concentration of chemical elements on the surface of pyrite crystals selected from veins of different types were investigated using digital images generated by means of ESEM. To achieve our goal, the distribution patterns of element concentration values of eight elements (Cu, Fe, Mn, Ni, P, S, Si and Ti) on the pyrite surface selected from B-type, D-type and H-type veins and veinlets were represented by multifractal spectra. Several multifractal parameters were calculated; however, the most significant ones are ∆ α and ∆ α L . These parameters are found to be higher in the D-type veins related to late phyllic alteration and mineralization in comparison with other veins and vein systems, indicating that the ore minerals containing Cu and Fe sulphides are highly enriched in D-type veins. This result is consistent with previous research on the area as well as new field observations, chemical and petrographic analysis carried out for this study. Therefore, the multifractal parameters, particularly ∆ α and ∆ α L , appear to be promising to discriminate between mineralized veins developed during different stages of hydrothermal activity which led to development of the porphyry system at Tongchang ore body.

The soil geochemical baseline is an important index in environmental assessment. Detailed baseline studies are necessary in large areas with complex geological settings, landforms and soil types. The Jianghan plain, a major industrial and agricultural region located in central China, has a soil geochemical baseline that has yet to be fully defined. The objective of this paper is to study the baseline of Cd, Pb and Zn in the topsoil of the Jianghan plain in a subarea using principal component regression (PCR). A total of 9030 samples were collected from the surface layer, and 2 soil profiles and 2 sedimentary columns were sampled near the Yangtze and Han rivers. Fifty-two elements and two parameters were analyzed. Data processing and the creation of spatial distribution maps of the elements were performed using MapGIS, R and SPSS software. The results show that the distributions of Cd, Pb and Zn are mainly controlled by parent material, drainage system and soil type. The study area is divided into 3 subareas, with factors reflecting the physico-chemical characteristics of the soil using factor analysis (FA). The geochemical baseline model is established in every subarea to predict the Cd, Pb and Zn values using principal component regression analysis (PCR); the exceptional values (as a result of anthropogenic input or mineralization) are distinguished by residuals ( γ ); and the natural background values and anthropogenic contributions are clearly distinguished. Therefore, the PCR method in these subareas is objective and reasonable, and the conclusion provides effective evidence of exceptional high values for further environmental assessment.

In the Early Ordovician Zhaogezhuang (赵各庄) Section of Tangshan (唐山), North China, the Yeli (冶里) Formation is composed of an entire third-order sequence, with facies ranging from the inner ramp restricted platform and open marine to the middle and even outer ramps. The Liangjiashan (亮甲山) Formation is dominated by highstand system tracts (HST) with predominantly inner ramp grain-shoal and lagoon facies. Analyzing the carbon and oxygen isotope during the whole-rock carbonate reveals the δ13C values in the Yeli Formation range from −7.11‰−0.76‰ (PDB), with the mean value at −2.98‰, while the δ18O values range of −9.09‰–−4.65‰ with the mean value at −6.12‰. The δ13C values in the Liangjiashan Formation range of −1.15‰−0.3‰, and the mean value of −0.57‰; the δ18O values are −8.76‰–−7.48‰, and the mean value is −8.06‰. The δ13C values in the Yeli Formation decrease, but at the bottom of the Liangjiashan Formation the values increase steadily. In the middle-upper formation, there is an extended fluctuation between 0–−1.00‰. The δ13C trend in the studied section is similar to that of the contemporary sections, except that it has much lower δ13C values and a more negative excursion. The correlation between the δ13C changes and the eustatic events, as well as the sedimentary facies, indicates that in the Tangshan area, the carbon isotope evolution can be attributabled to the processes of the eutrophic sea/oligotrophic sea, the seafloor organism-mediated oxidation in shallow water and the organic reduction after maximum flooding. The changes in the carbon isotope contents were primarily affected by the regional relative sea level changes. Compared to the other coeval data, the Early Ordovician of the Tang shan area is also severely depleted in 18O, with all of the δ18O sample values being below −5‰, except for one sample with a value of -4.65‰. With the ancient seawater having a δ18O value of −5.5‰ (SMOW), it is reasonable to delineate a temperature of less than 37 °C.

Selenium can be emitted to the environment during the combustion of Se-rich stone coal, both polluting the air and wasting a scarce resource of Se. In this work, the nanosized metal oxides ZnO, Al2O3, and Fe3O4 were combined with CaO to form composite materials. These were investigated as sorbents for the removal of Se from the flue gases generated by Se-rich stone coal combustion over the temperature range of 700–1000 °C during laboratory scale testing. It was found that these composite materials, especially those containing ZnO and Fe3O4, exhibited higher adsorption efficiency than pure CaO. The highest adsorption efficiency of 95.46% was obtained with the CaO-ZnO composite sorbent under optimized experimental conditions. FT-IR and X-ray diffraction results indicated that the adsorbed Se was predominantly in the form of CaSeO3, with a minor amount of ZnSeO3. Both the formation of ZnSeO3 and the enhanced reaction interface contribute to the higher adsorption of Se on the CaO-ZnO composite sorbent as comp...

Extracellular phenol oxidases play an important role in the soil carbon cycle. How phenol oxidase activity in peatlands will respond to increased aeration induced by water-table drawdown or droughts if global warming continues remains unclear. We investigated the short-term effects of drought induced acidification on phenol oxidase activities of a Sphagnum-dominated peatland in central China. The results indicated a significant acidification induced by drought, with a decline in the average pH value from 5.67 ± 0.08 under waterlogging to 4.84 ± 0.08 in droughted peat. In addition, drought-treated peat had a lower average value of phenol oxidase activities compared to the waterlogging-treated peat (mean values of 0.1404 ± 0.0305 and 0.2623 ± 0.0324 μmol diqc min−1 g−1, respectively). The decreased phenol oxidase activities were mainly attributed to the acidification induced by drought. However, the declines in phenol oxidase activity did not lead to the reduction of the degradation in the deeper peat. Under drought conditions, a considerable part of the adsorbed phenolics, consisting primarily of high molecular-weight organic substances with phenolic groups, were further degraded into smaller-sized or lower molecular weight hydrophilic fractions in the vicinity of the water table. Our results highlight the important role of the water table position in peat decomposition processes. Even with lower activities of phenol oxidase, the decomposition processes were able to effectively keep on going as long as there was sufficient supply of water, oxygen and nutrients.