Search

Community dominant plants and their ecological niche research is the focus of community ecology research. To explore the niche characteristics of desert dominant plants and the relationship between them and soil factors in Qaidam Basin, and to provide a basis for the construction of desert plant communities and the sustainable management of natural resources in Qaidam Basin. Taking 13 desert plant communities in Qaidam Basin, Qinghai Province as the research objects, this paper analyzed the characteristics of desert plant communities and dominant species based on soil physical and chemical properties, and calculated the niche width and niche overlap of dominant plants. The dominant plants are, Haloxylon ammodendron, Tamarix chinensis, Achnatherum splendens, Poacynum hendersonii, Reaumuria songonica, Phragmites australiss, Sympegma regelii, and Ajania Tenuifolia, Artemisia sphaerocephala, Ceratoides latens, Pearl russianthistle, Scirpustriquter. There were different degree of niche overlap among species in the community. In addition, CCA sequencing showed that different species had different requirements on the environment, and the distribution of dominant species was mainly affected by soil total nitrogen and soil organic matter.

Objective: Through the investigation, determination and analysis of heavy metals in the soil of typical alpine grassland community, five kinds of alpine grasslands with different degeneration degree of Maduo County in Alpine area, two kinds of alpine grassland with high Maqu County, high Alpine desert along the coast of Qinghai Lake, alpine thickets in the yellow South region, Alpine wetlands, The condition of soil heavy metals in alpine meadow and other communities is analyzed, which provides scientific guidance for the ecological protection measures of typical alpine grassland communities, and provides a basis for the sustainable utilization of Alpine grassland. Methods: The content of various kinds of heavy metals in soil samples was determined by ICP-MS, and the pollution status of heavy metals was analyzed by means of single factor pollution index method, Nemero comprehensive pollution index method and potential ecological risk index method by using Excel. Results: (1) The content of Cd in Maduo, Maqu, Qinghai Lake and Huangnan was 1.74, 0.97, 1.84 and 1.06 times times the soil environment background respectively, and the content of Hg in Maqu was 1.36 times times that of soil environmental background value. The variation coefficient of Hg and Pb in Maqu and the coefficient of variation of Cd in Qinghai Lake are more than 100%, which is in the degree of high variation, which is greatly influenced by man. (2) The highest total pollution index in the 4 sample places was in the area of MA diversity, at 1.33. The second is the Huangnan sample, with an exponential value of 0.86. The Nemero comprehensive pollution Index of the Maqu sample is 0.77. The index value of Qinghai Lake sample is the lowest, at 0.61. (3) The highest potential ecological hazard index is the most diverse, in 0-10, 10-20, 20-30cm three soil layers are 96.96, 103.58, 102.46, Maqu in 0-10, 10-20cm soil, the potential ecological hazard index is 65.70, 71.01, the potential ecological hazard index of Huangnan in three soil layer is 78.23, 73.42 and 72.84 respectively, which refers to the smallest value of Qinghai Lake sample, three, 51.07 and 51.72 in 51.48 soil layer respectively. Conclusion: The Nemero comprehensive pollution Index of Qinghai Lake sample is less than 0.7, at the level of cleanliness, the exponential value of Huangnan and Maqu two samples is between 0.7~1, at the level of cordon, and the exponential value of ma variety is between 1~2, at the level of mild pollution. The comprehensive potential ecological hazard index of 80~160 has the potential ecological risk of strength, and the exponential value of the other three samples is between 40~80, which has medium potential ecological risk. Generally, the pollution degree of heavy metals is small in the whole alpine grassland area.

A portable electrode with usability, availability, and high-sensitivity is of great significance for effective on-site detection in practical situations. In this paper, a novel flexible, disposable sensor for Cd2+ and Pb2+ with ultrahigh sensitivity and a fast response, based on acid-etched Fe/Fe2O3 encapsulated into a disposable carbon cloth electrode, has been successfully fabricated. Differential pulse anode stripping voltammetry (DPASV) was used to investigate the stripping behavior of Cd2+ and Pb2+, achieving high sensitivity for Cd2+ and Pb2+ (338.7 and 408.0 μA mM−1 cm−2) with limits of detection (LODs) of 0.42 ppb and 0.50 ppb, respectively. Meanwhile, remarkable stability and reproducibility were obtained. Such an electrode can detect Cd2+ and Pb2+ in actual water samples so this is a good candidate to act as a simple and convenient sensor for general applications. More importantly, the novel disposable electrode exhibited the unique advantages of convenience, portability, and reliability compared to a conventional electrode, which may make it an alternative advantageous choice for practical on-site detection. [ABSTRACT FROM AUTHOR]

A portable electrode with usability, availability, and high-sensitivity is of great significance for effective on-site detection in practical situations. In this paper, a novel flexible, disposable sensor for Cd2+ and Pb2+ with ultrahigh sensitivity and a fast response, based on acid-etched Fe/Fe2O3 encapsulated into a disposable carbon cloth electrode, has been successfully fabricated. Differential pulse anode stripping voltammetry (DPASV) was used to investigate the stripping behavior of Cd2+ and Pb2+, achieving high sensitivity for Cd2+ and Pb2+ (338.7 and 408.0 μA mM−1 cm−2) with limits of detection (LODs) of 0.42 ppb and 0.50 ppb, respectively. Meanwhile, remarkable stability and reproducibility were obtained. Such an electrode can detect Cd2+ and Pb2+ in actual water samples so this is a good candidate to act as a simple and convenient sensor for general applications. More importantly, the novel disposable electrode exhibited the unique advantages of convenience, portability, and reliability compared to a conventional electrode, which may make it an alternative advantageous choice for practical on-site detection. [ABSTRACT FROM AUTHOR]

A novel electrochemical carbon cloth (CC) analysis device (eCAD) is proposed for the determination of Pb2+ in environmental water samples, which was assembled using a single-step functional CC as both the sensing and the substrate material. The modified CC was characterized by scanning electron microscopy, X-ray photoelectron spectroscopy, Raman spectra, and electrochemical impedance spectroscopy. The increase in electrochemical activity is due to the increased defective extent and excellent electrochemical activity of CC. Under optimum conditions (viz. a pH value of 4.5, deposition time of 160 s), the sensor is capable of determining Pb2+ by differential pulse anodic stripping voltammetry (DPASV) at a typical working potential of − 1.0 V (vs. Ag/AgCl). Response is linear from 5.0 × 10−9 to 3.0 × 10−6 M Pb2+, and the detection limit is 4.8 nM (at S/N = 3). The sensor was successfully applied to the determination of Pb2+ in real samples, with apparent recoveries from 96.0 to 102.0% and a relative standard deviation of less than 3.4%. In addition, the integration of the sensor with signal collection components has enabled us to realize on-site analysis of Pb2+, which is highlighted as a new generation of electrode platform for the development of a portable analysis device. Graphical abstract [ABSTRACT FROM AUTHOR]

The porous microspherical Nitrogen and Phosphorus‐co‐doped NiFe2O4/Single‐Walled Carbon Nanotubes (NP‐NiFe2O4/SWNTs) had been fabricated. Nitrogen (N) and phosphorous (P) were co‐doped to increase the active sites. And SWNTs hybrid was to obtain the enhanced conductivity, large specific surface area and more active sites. The hierarchical, porous structure and highly conductive SWNTs enables efficient transport of the electrons generated during oxygen evolution reaction (OER). Thus, NP‐NiFe2O4/SWNTs was demonstrated as a high‐performance catalyst for OER with a small overpotential of 247 mV at 10 mA cm−2 and low Tafel slope of 83.6 mV dec−1. The outstanding performance of NP‐NiFe2O4/SWNTs can also made it serve as anode for water splitting at a cell voltage of 1.595 V, which surpasses the precious RuO2 and Pt/C. That's dope! Porous microspherical nitrogen and phosphorus‐co‐doped NiFe2O4/single‐walled carbon nanotubes have been developed for efficient oxygen evolution reaction, which showed the strategy to improve the catalytic activity by designing and tuning the hierarchical structure, composition, conductivity and active sites. [ABSTRACT FROM AUTHOR]

Objective: To explore the characteristics of blood oxygen level-dependent magnetic resonance imaging (BOLD-MRI) in healthy native kidneys. Methods: Seventy-nine patients without chronic kidney disease underwent BOLD-MRI with T2* spoiled gradient recalled echo sequences. BOLD images were analyzed using R2*map software to produce an R2* pseudo-color map. Cortical and medullary R2* values were analyzed in both kidneys and in both sexes. Different regional R2* values in the cortex and medulla were also analyzed. Physiological indices including age, height, weight, body mass index, body surface area, and estimated glomerular filtration rate (eGFR) were recorded. Correlations between R2* value and physiological indices were determined. Results: Renal cortical R2* values were lower than values in the medulla (p < 0.001). Female and male cortical R2* values were also lower than the corresponding values in the medulla (p < 0.001). Renal medullary R2* values in the lower renal pole were lower than values in the middle and upper poles (p = 0.001). Age was positively correlated with R2* values in the medulla (r = 0.32, p = 0.004). eGFR was negatively correlated with both cortical R2* values (r = -0.26, p = 0.02) and medullary R2* values (r = -0.29, p = 0.009). Conclusions: BOLD-MRI can directly visualize renal oxygenation. There was variation in the oxygenation of different regions of the kidney. Renal cortical and medullary oxygenation in healthy kidneys decreased with patient age. eGFR also decreased with patient age. © 2014 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Objective To explore the characteristics of blood oxygen level dependent (BOLD) magnetic resonance imaging (MRI) in healthy native kidneys. To investigate the relationship between BOLD-MRI and common physiological indexes. Methods GE 3.0T MRI scanner and Torsopa phased-array coil were employed to acquire renal coronal T1WI and BOLD image. Ninety patients who were ruled out chronic kidney diseases underwent BOLD-MRI with T2*-spoiled gradient recalled echo (T2*SPGR) sequence. BOLD images were analyzed on R2*map software. Cortical and medullary R2* values were analyzed in bilateral kidneys and in different gender. Different regional R2* values in cortex and medulla were also analyzed. Physiological indices including age, body height and weight, body mass index (BMI), body surface area (BSA), estimated glomerular filtration rate (eGFR) were recorded. Correlation between R2* value and physiological indices were analyzed. Results Bilateral renal cortical R2* values [left (16.56±1.40) Hz and right (16.66±1.28)Hz, respectively] were less than values in medulla [left (28.82±3.71)Hz and right (28.36±3.72)Hz, respectively]. Female and male cortical R2* values [female (16.55±1.30Hz) and male (16.66±1.38)Hz, respectively] were also less than corresponding values in medulla [female (28.46± 3.64) Hz and male (28.70±3.78) Hz, respectively]. In bilateral renal medullary region, R2* values in low pole (27.29±3.05) Hz was less than values in middle (29.32±3.47) Hz and upper pole (29.16±4.21)Hz (F =15.184, P < 0.001). Age was positively correlated with R2* values in medulla (r =0.284, P =0.002). However, eGFR was negatively correlated with medullary R2* value (r =-0.232, P =0.007). Conclusion R2* values reflected the levels of renal partial pressure of oxygen and assessed the degree of renal ischemia. BOLD MRI could offer a simple, convenient and noninvasive method for to evaluate renal oxygen metabolism in cortex and medulla. [ABSTRACT FROM AUTHOR]