Responses of soil bacterial communities,enzyme activities,and nutrients to agricultural-to-natural ecosystem conversion in the Loess Plateau,China

Journal of Soils and Sediments - Soil microbial communities play critical function during nutrient cycling. However, with the increasing nutrient input into terrestrial ecosystems from human...     

Semi-Analytical Solutions for Two-Dimensional Transport and Transformation of Contaminants in Soil Medias Associated with Large-Strain Deformation

For the understanding of contaminant transport and transformation through landfill liner soils, most models are proposed with one-dimensional solutions. However, for large-scale contamination analysis, the one-dimensional analytical equations are not valid owing to the restriction of contaminants moving in horizontal direction. Thus, semi-analytical solutions for two-dimensional transport and transformation of contaminants through soil media with the consideration of large-strain deformation have been developed. To achieve this, Gibson’s large-strain consolidation theory is applied to capture the deformation of soil media under loading, with self-weight effects being taken into account. Transport and transformation of dissolved or sorbed contaminates in fully saturated finite soil medias are captured by extending a well-developed advection-dispersion model in two-dimensional space. The proposed analytical solutions are validated through simulating the process of coupled transport-transformation process of contaminants and consolidation of a finite soil layer. Profiles of contaminant concentration for different cases have been compared and discussed. The resulting simulation shows that large-strain deformation would restrict the transport and transformation of contaminants significantly, in both horizontal and vertical directions. Parameter studies also indicate that, with the increasing depth of soil layer, the breakthrough time for contaminants increases dramatically; diffusion coefficients affect the two-dimensional distributions of contaminant concentration and fate of contaminant in layered soil significantly. The numerical findings of this study can provide proper suggestions for the design of landfill liners.     

Cuprous Oxide-Modified Diatomite Waste from the Brewery Used as an Effective Adsorbent for Removal of Organic Dye: Adsorption Performance,Kinetics and Mechanism Studies

Cuprous oxide-modified diatomite waste (Cu₂O-DW) as a low-cost and effective adsorbent was prepared via a hydrothermal route combined with acid-alkali treatment. The microstructure and surface properties of the obtained Cu₂O-DW composite was characterized by Brunauer-Emmett-Teller, scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. The adsorption behaviors of three different types of dyes such as cationic dye methyl blue (MB), anionic dye acid orange (AO), and reactive dye reactive yellow (RY) onto the as-prepared Cu₂O-DW were investigated. Several experimental parameters such as contact time, adsorbent dosage, initial dye concentration, and initial pH values were systematically estimated. The experimental results indicated that as-prepared Cu₂O-DW have a better adsorption performance for MB, AO, and RY. Moreover, the kinetic and isotherm models were also used to account for the adsorption mechanism of dye molecules onto Cu₂O-DW. The results demonstrated that three different dyes are all fitted well with pseudo-first-order kinetic model. Additionally, the Langmuir and Freundlich isotherm model is more suitable for describing the adsorption process of RY and MB on the as-prepared Cu₂O-DW, respectively, and the AO adsorption is propitious to the D-R isotherm model. The value of adsorption energy (E?<?8 kJ mol^?1) confirmed that the physical adsorption is dominator during the adsorption process. The findings of the study demonstrated that the synthesized Cu₂O-DW composite can be a promising adsorbent for the removal of organic dyes from wastewater and it provided a sustainable development method for cycling the diatomite waste from the brewery.     

Environmental Risk Assessment of Emerging Contaminants Using Degradation Data

The degradation behavior of an emerging contaminant is a key factor in its environmental risk assessment. Existing risk assessment methods based on EC degradation data commonly neglect the time-varying volatility of the degradation, the possible correlations in degradation between different ECs, and the estimation errors. To fill the gaps, this paper proposes an EC risk assessment framework based on the Wiener process. We first focus on degradation data from competitive experiments, which are adopted to evaluate a useful risk indicator, i.e., the bimolecular rate constant of a degradation reaction. A two-dimensional Wiener process model is developed to capture the degradation behaviors of the target EC and a reference contaminant in the experiment. Point and interval estimations of desired quantities, including the rate constant and the degradation half-life, are developed. We further extend the model to the multivariate case, which is applicable to waste water treatment where multiple ECs degrade in a mixed solution. A risk indicator for the mixed solution is proposed, based on which a minimal treatment time can be determined. Both point and interval estimation procedures of the risk indicator and the minimal treatment time are proposed. Two EC degradation datasets are used to demonstrate the proposed methodologies.   Supplementary materials accompanying this paper appear on-line.     

Reducing CH<Subscript>4</Subscript> and CO<Subscript>2</Subscript> emissions from waterlogged paddy soil with biochar

Purpose  

A potential means to diminish increasing levels of CO₂ in the atmosphere is the use of pyrolysis to convert biomass into biochar, which stabilizes the carbon (C) that is then applied to soil. Before biochar can be used on a large scale, especially in agricultural soils, its effects on the soil system need to be assessed. This is especially important in rice paddy soils that release large amounts of greenhouse gases to the atmosphere.     

Evaluation of the durability of the <Emphasis Type="Italic">Barley yellow dwarf virus</Emphasis>-resistant <Emphasis Type="Italic">Zhong ZH</Emphasis> and <Emphasis Type="Italic">TC14</Emphasis> wheat lines

Serial passage experiments (SPE) of a Barley yellow dwarf virus-PAV (BYDV-PAV) isolate were performed on Zhong ZH and TC14 wheat lines to evaluate the durability of their resistance to BYDV. At different passage numbers (from the 2nd to the 114th), biological properties of the produced isolates were recorded either by monitoring infection percentages and virus titers of the first 3 weeks of viral infection or by measuring their impact on yield components. Statistical analyses using the area under pathogen progress curves and the area under concentration progress curves demonstrated that these two resistant lines induce, after only a few passages, a selection of variant(s) with significantly modified infection abilities. Isolates resulting from SPE performed on these lines induced important decreases of yield components. These results indicate that the use of Zhong ZH and TC14 lines in BYDV-resistant breeding programmes should be approached with caution.     

HPLC测定复方磺胺间甲氧嘧啶钠可溶性粉含量

建立复方磺胺间甲氧嘧啶钠可溶性粉中磺胺间甲氧嘧啶钠（以磺胺间甲氧嘧啶计）和甲氧苄啶含量的HPLC检测方法,采用Inertsil C18色谱柱（4.6mm×250mm,5μm）,以乙腈：0.017mol/L磷酸液（20：80）（按1‰的比例加入三乙胺）为流动相,流速为1mL/min,检测波长为230nm。在该色谱条件下,两种药物分离很好,磺胺间甲氧嘧啶在24.89～248.9μg/mL之间,甲氧苄啶在5～50μg/mL之间,线性良好（r〉0.99999）,添加回收率在97.46%～100.45%之间。该方法快速简便,准确可靠,能够满足实际样品的检测要求。     

Characteristics of nucleotides and amino acids in cDNA sequence of xyloglucan endotransglycosylase cloned from <Emphasis Type="Italic">Anthocephalus chinensis</Emphasis>

Xyloglucan endotransglycosylase is an identified relaxation factor with functions of easing and extending of plant cell walls.Its activities are directly related to plant growth and elongation of organisms.Anthocephalus chinensis is a tall and fast growing evergreen tree species.We cloned the full cDNA sequence of AcEXT genes which is abundantly expressed in the cambium of A.chinensis.The sequence analysis of nucleotides and amino acids revealed the presence of a 1396 bp full cDNA sequence,including a 960 bp complete open reading frame(ORF) encoding a 320 amino acid protein.The deduced amino acid sequence of AcXET was homologous to the other known XET proteins and contained the conserved EIDFE catalytic site which was specific to all the XETs.Our data should serve as a foundation for further insight into AcXET gene molecular mechanisms during wood formation and cell wall engineering of woody plants.     

LINC24065在体细胞核移植牛中的异常表达

旨在揭示DLK1-DIO3印记域上一个新的长链非编码RNA(long noncoding RNA,lncRNA)LINC24065在自然繁殖牛(natural reproduction,NR)与体细胞核移植牛(somatic cell nuclear transfer,SCNT)中的组织表达与印记状态,对进一步了解DLK1-DIO3印记域在供体核重编程中的作用提供一定的理论基础。本研究以自然繁殖牛的大脑组织为试验材料,利用RACE和RT-PCR技术,在牛的DLK1-DIO3印记域内鉴定了一个新的印记的lncRNA基因,命名为LINC24065。用基于SNP(single nucleotide polymopisms)的RT-PCR产物直接测序方法分析LINC24065在自然繁殖牛和体细胞核移植牛组织中的表达及印记状态。序列分析发现,LINC24065编码6个可变剪接体,并在自然繁殖牛被检测的7个组织中都表达,而在体细胞核移植牛组织中没有检测到可变剪接体LINC24065-V3,且其它5个剪接体呈现组织特异性表达。印记状态分析发现,LINC24065在自然繁殖牛和体细胞核移植牛的7个组织中均为单等位基因表达,但在体细胞核移植牛的大脑组织中出现了与其他组织亲本来源不同的单等位基因表达。研究结果说明,LINC24065基因在体细胞核移植牛的大脑中出现了印记紊乱,并且剪接体在组织中的表达也发生了改变。以上研究结果说明LINC24065基因与体细胞核移植牛的发育异常有关。