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Purpose Telomerase is reactivated in non-small cell lung cancer (NSCLC), and it increases cell resistance to irradiation through protecting damaged telomeres and enhancing DNA damage repair. We investigated the radiosensitizing effect of BIBR1532, a highly selective telomerase inhibitor, and its corresponding mechanism in NSCLC. Methods and Materials Cell proliferation, telomerase activity, and telomere dysfunction-induced foci were measured with CCK-8 assay, real-time fluorescent quantitative polymerase chain reaction, and immunofluorescence. The effect of BIBR1532 on the response of NSCLC cells to radiation was analyzed using clonogenic survival and xenograft tumor assays. Cell death and cell senescence induced by BIBR1532 or ionizing radiation (IR), or both, were detected with western blotting, flow cytometry, and senescence-association β-galactosidase staining assay. Results We observed dose-dependent direct cytotoxicity of BIBR1532 at relatively high concentrations in NSCLC cells. Low concentrations of BIBR1532 did not appear toxic to NSCLC cells; however, they substantially increased the therapeutic efficacy of IR in vitro by enhancing IR-induced apoptosis, senescence, and mitotic catastrophe. Moreover, in a mouse xenograft model, BIBR1532 treatment synergized with IR at nontoxic dose levels promoted the antitumor efficacy of IR without toxicity to hematologic and internal organs. Mechanistically, lower concentrations of BIBR1532 effectively inhibited telomerase activity and increased IR-induced telomere dysfunction, resulting in disruption of chromosomal stability and inhibition of the ATM/CHK1 (ataxia-telangiectasia-mutated/Checkpoint kinase 1) pathway, which impaired DNA damage repair. Conclusions Our findings demonstrate that disturbances in telomerase function by nontoxic dose levels of BIBR1532 effectively enhance the radiosensitivity of NSCLC cells. This finding provides a rationale for the clinical assessment of BIBR1532 as a radiosensitizer.

N2O emissions have increased significantly over the last decades, with much of the increase being ascribed to the expansion in agricultural land. Agricultural water management has significant influence on N2O emissions, hence the investigation of N2O emissions and the underlying production mechanisms under different irrigation managements would provide insights for N2O emission reduction and rational water usage. Here, we used the stable isotope method to evaluate the N2O isotopic signatures and the site preference, to clarify the N2O emission dynamics and the N2O source partitioning under different irrigation managements. We applied a furrow irrigation system and a drip irrigation system to maintain two different soil water conditions, allowance of dry-wet cycles and relatively stable water conditions, respectively. We found that the N2O emission was significantly decreased under drip irrigation compared to furrow irrigation with cumulated N2O flux of 526.3 mg m−2 and 571.0 mg m−2, respectively. In general, furrow irrigation with its dry-wet alternations promoted N2O emissions, while drip irrigation created a relatively stable environment that reduced N2O emissions. The intramolecular 15N isotopic composition of N2O was used to partition the relative contribution of denitrification and nitrification. Nitrification dominated the processes driving N2O production under both treatments, nearly accounting for 76% up to 100% during the initial N2O peaks. Effective measure for mitigating N2O emissions from the investigated vegetable field could be obtained by replacing the traditional furrow irrigation with drip irrigation.

The accumulation of serial remote sensing images provides plentiful data for discovering sequential spatial patterns in various fields such as agricultural monitoring, urban development, and vegetation cover. Otherwise, traditional sequential pattern-mining algorithms cannot be directly or efficiently applied to remote sensing images. In this study, we propose a pixel clustering-based method to improve the efficiency of mining spatial sequential patterns from raster serial remote sensing images (SRSI). Firstly, the images are compressed by using the Run-Length coding schema. Then, pixels with identical sequences are clustered by means of the Run-length code-based spatial overlay operation. Finally, a pruning strategy is proposed, to extend the prefixSpan algorithm to skip unnecessary database scanning when mining from pixel groups. The experimental results indicate that the method presented in this paper could extract spatial sequential patterns from SRSI efficiently. Although accurate support rates for the patterns may not be obtained, our method could ensure that all patterns are extracted with a lower time cost.

In the Loess Plateau of China, conventional tillage is defined as the tillage without crop residues left on the soil surface and ploughed twice a year. The use of alternative practices is a way to reduce soil erosion. Our objectives were to assess the long-term impacts of different soil tillage systems on soil physical and hydraulic characteristics, emphasizing management practices to improve the soil physical qualities (reduce bulk density and increase stability of aggregate) under the conservation tillage system in the Loess Plateau of China. Conventional tillage (CT), no tillage (NT), and sub-soiling (SS) were applied in this experiment. Soil wet aggregates distribution and stability, soil organic carbon (SOC) content, soil water retention curves and pore size distributions were measured. The results showed that in the 0–10 cm and 10–20 cm depth soil layers, NT and SS treatments showed a significantly higher proportion of wet aggregates >250 μm (macroaggregates) compared to CT. In these two layers, the proportion of wet aggregates 250 μm than within the 250–53 μm and

Fertigation can improve water use efficiency (WUE) compared with conventional separate supply of water and fertilizers to plants. Yet the mechanisms underlying the improved WUE under fertigation remain largely elusive. Therefore, the impact of water and nitrogen (N) on leaf gas exchange, plant water relations, ABA signaling and WUE as well as leaf δ13C and δ18O were investigated in order to unravel how water and N modulate plant WUE. Results showed that reduced soil water regimes under N fertigation caused partial closure of stomata via decreased plant water status and intensified root-to-shoot ABA signaling, resulting in improved intrinsic WUE (WUEi). Decreased soil water regimes increased plant WUE (WUEp) and leaf δ13C, and the increased leaf δ13C was due to reduced gs and/or higher specific leaf N content enhanced photosynthetic capacity. Leaf δ18O and δ13C further indicated that the significant increase in leaf δ13C under the reduced water regimes was caused primarily by reductions in gs compared with N nutrition. Therefore, gs rather than N nutrition predominated regulation of plant WUE under fertigation. Moderate soil water regimes with sufficient N supply are recommended for fertigation in terms of achieving high fresh fruit yield, WUE and nutrient uptake.

Different environmental changes may have some consistent effects on soil microbial community, which remains largely unexplored. Here, we report a novel and general pattern that different environmental changes consistently selected for the sub-dominant soil bacterial phyla. We mimicked 16 types of environmental changes relevant to the Eurasian steppe ecosystem, including removing different number of plant functional groups, mowing, nitrogen adding, phosphorus adding, watering, warming, and some of their combinations. While the absolute abundance of each of the four dominant bacteria phyla (Acidobacteria, Actinobacteria, Chloroflexi, and Proteobacteria) did not show a consistent response to these treatments, that of the five sub-dominant phyla (Bacteroidetes, Firmicutes, Gemmatimonadetes, Nitrospirae, and Planctomycetes) showed a consistent increase. The dominant phyla had high abundances of genes responsible for energy production/conversion and transcription, exhibiting oligotrophic traits; in contrast, the sub-dominant phyla had high abundance of 16S rDNA sequences, which could be due to greater rRNA copy number or smaller genomes, showing large growth/propagation potential and copiotrophic trait. Stochastic processes (e.g., random birth, death, colonization) played more important roles in structuring the sub-dominant than dominant phyla, and the treatments promoted the stochastic processes. The copiotrophy and stochasticity of sub-dominant phyla led to their positive responses to the treatments.

Objective This study aimed to investigate the physical relation and mechanism of bactericidal activity on pathogenic E. coli by ultrasonic field with whey protein isolate (WPI). Methods Ultrasound treatment was performed under the conditions of intensity at 65 W/cm2, pulse duty ratio at 0.5 for 0–15 min with WPI concentration ranged from 0 to 10%. Viscosity, granularity, surface hydrophobicity, free radical scavenging activity, and thermal denaturation were assessed by rotational viscometer, Malvern Mastersizer 2000 particle size analyzer, fluorescent probe ANS method, DPPH method, and differential scanning calorimetry, respectively. Results The thermal denaturation of WPI was not altered by ultrasound field, but the viscosity of WPI was increased upon 10 min treatment. Additionally, its ability to scavenge free radicals and hydrophobicity were increased. The result also showed that the bacteria viability was improved by WPI during ultrasound treatment. However, the WPI protection was decreased by the prolonged treatment. Conclusion Ultrasound treatment resulted in the increasing of the viscosity, free radicals scavenging activity and hydrophobicity of WPI which led to reduced bactericidal activity on E. coil, while WPI protection was disintegrated by prolonged treatment.

It is a central goal of current community ecology to explore the pattern and mechanism of community response to anthropogenic disturbances. Most researches focus on the response of community composition, which is based on the presence/absence or relative abundances of different species. However, the response of species-identity-independent community structure, such as the rank-abundance distribution, remains relatively understudied. We conducted a ten-year nitrogen addition experiment in a temperate steppe, with nine nitrogen rates under fencing (un-mowed) or mowing conditions. Mowing and nitrogen addition significantly altered both the composition and structure of plant communities. While the relative importance of stochastic change in community composition under mowing was not significantly different from that under fencing, the relative importance of stochastic change in community structure under mowing was significantly larger than that under fencing. Overall, our results demonstrated that mowing led to different drivers for the community composition and structure, meaning that mowing promoted the stochastic allocation of material and energy in primary producers in the grassland ecosystem.

Increasing atmospheric nitrogen (N) deposition causes profound changes in the plant community, significantly threatening the terrestrial ecosystem function and stability worldwide. Random migration is a primary determinant of plant community assembly in the neutral model. However, whether its role is affected by N deposition is obscure. Therefore, the effects of eight N application rates (0, 1, 2, 3, 5, 10, 15, and 20 g N m−2 yr−1) on the estimated migration rate of plant community were examined in a long-term field study in a semiarid steppe. Our results indicated that N addition significantly impacted the estimated migration rate (F = 4.89, P

Fencing facility has been widely employed in steppes. However, the effects of fencing facility on plant species and soil organic carbon (SOC) have been rarely understood in steppes. Using soil sampling and plant quadrat clipping methods, in this study, we investigated the effects of fencing facility on the distributions of plant species and SOC in the temperate steppes of the Inner Mongolia. Plant biomass significantly increased with approaching fencing facility and was obviously higher in the leeward (south) than windward (north) sides. Perennial grasses accounted for approximately 68%–76% of the total aboveground biomass in both sides of fencing facility. SOC content also significantly increased with approaching fencing facility in the 0–10 soil layer but slightly increased in the 10–30 cm soil layer. Wind erosion and dust storm did markedly neither change the fractions of soil texture nor cause the difference in SOC content between the windward and leeward sides. Fencing facility increased SOC storage by 16.5% and 9.1% at 0.1 and 0.5 m locations relative to at 3 m location in the 0–10 cm soil layer, respectively. Edge effect is suggested as a potential mechanism driving the variations of plant species and SOC in both sides of fencing facility.

Nicotinamide (NAM) is the amide of nicotinic acid and a predominant precursor for NAD(+) biosynthesis via the salvage pathway. Sirt1 is a NAD(+)-dependent deacetylase, playing an important role in regulating cellular functions. Although hepatoprotective effect of NAM has been reported, the underlying mechanism remains elusive. ER stress, induced by saturated fatty acids, in specific palmitate, plays a pathological role in the development of nonalcoholic fatty liver disease. This study aims to determine the effect of NAM on palmitate-induced ER stress in hepatocytes and to elucidate molecular mechanisms behind. Both HepG2 cells and primary mouse hepatocytes were exposed to palmitate (conjugated to BSA at a 2:1 M ratio), NAM, or their combination for different durations. Cellular NAD(+) level, Sirt1 expression/activity, ER stress, as well as cAMP/PKA/CREB pathway activation were determined. NAM increased Sirt1 expression and enzymatic activity, which contributes to the ameliorative effect of NAM on palmitate-triggered ER stress. NAM increased intracellular NAD(+) level in hepatocytes, however, blocking the salvage pathway, a pathway for NAD(+) synthesis from NAM, only partially prevented NAM-induced Sirt1 upregulation while completely prevented NAD+ increase in response to NAM. Further mechanistic investigations revealed that NAM elevated intracellular cAMP level via suppressing PDE activity, leading to downstream PKA and CREB activation. Importantly, cAMP/PKA/CREB pathway blockade abolished not only NAM-induced Sirt1 upregulation, but also its protective effect against ER stress. Our results demonstrate that NAM protects hepatocytes against palmitate-induced ER stress in hepatocytes via upregulating Sirt1. Activation of the cAMP/PKA/CREB pathway plays a key role in NAM-induced Sirt1 upregulation.

Swine feedlots that have operated in the absence of adequate disposal facilities are being demolished under the new environmental protection policies in China. The environmental behavior and transmission risks of antimicrobial resistance genes (ARGs) are unclear for these abandoned swine feedlots. We examined 40 soil samples that originated from the soils adjacent to two abandoned and two working swine feedlots to explore: 1) the distribution patterns and vertical transmission of 17 ARGs and two integron genes and 2) the bacterial community as well as their correlation with environmental factors and target genes. We found that seven and nine out of forty-eight subtypes of veterinary antimicrobials (VAs) were detected in the soil near abandoned feedlots and working feedlots, respectively. Three tet genes (tetM, tetO and tetW) were particularly enriched in the soil adjacent to both abandoned and working feedlots. The tetM gene was a "hub" on the network of the topsoil. The relative abundance of Firmicutes ranged from 2.5 to 9% in the soil near two Beijing feedlots and was significantly higher than that in the upstream blank control (CK soil) (ANOVA, p 0.05). Overall, the ARG distribution patterns in the soils adjacent to abandoned swine feedlots were similar to the working feedlots. This study offers basic information on the prevalence and transmission risk of ARGs in abandoned swine feedlots and provides a reference for the restoration and reuse of demolished feedlots.

The adoption of conservation tillage is promising for soil management system in the Loess Plateau of China; however, how conservation tillage influences the molecular structure contributes and long-term stabilization of soil organic matter (SOM) is still not clear in this area. In this study, experimental plots were continually cultivated with winter wheat ( Triticum aestivum L.) and soil samples were collected in September 2009 and September 2015, 10 and 16 years after the experiment was initiated, respectively. Four treatments were applied: reduced tillage (RT), no tillage (NT), sub-soiling (SS) and conventional tillage (CT). Soil samples were physically fractionated into five fractions: free light fraction (FLF), occluded light fraction (OLF), coarse sand particulate organic matter (c-POM), fine sand particulate organic matter (f-POM) and mineral associated organic matter + silt + clay (m-SOM). The soil organic carbon (SOC) stocks were analysed in SOM fractions and bulk soil (BS). Solid state 13 C cross polarization/total sideband suppression nuclear magnetic resonance ( 13 C CP/TOSS NMR) spectroscopy was applied to determine the abundance of different forms of carbon (C) (carboxyl C, O/N-alkyl C, aromatic C and alkyl C) in the soil physical fractions. The SOC stocks in the 0–30 cm layer were influenced by the tillage systems. Although there were no significant differences in SOC stocks among these four treatments in the 0–10 and 10–20 cm layers in first 10 years, after 16 years, the SOC stocks were highest in the SS and NT treatments in the 0–10 cm layer. As the duration of the experiment increased from 2009 to 2015, the SOC content of m-SOM-C fraction under RT and CT also increased. As determined by 13 C NMR, in the light fractions (FLF to OLF), the abundance of aromatic C increased when the abundance of O/N-alkyl C declined and there was a higher aromatic C/O/N-alkyl C ratio. A gradual increase in the abundance of alkyl C of heavy fractions was accompanied by a decrease in aromatic C, which might be due to the microbial by-products deposited on mineral surface in the soils. In addition, a higher SOM preservation were shown in conservation tillage (NT and SS) by our NMR data. Particular interesting were the results of the light and c-POM fractions, in which conservation tillage showed a higher abundance of O/N-alkyl C and a lower aromatic C/O/N-alkyl C ratio in these two fractions compared with conventional tillage (RT and CT).However, these changes were not evident in the heavy fractions. The changes in the chemical structures of the light and c-POM fractions were possibly due to the retention of crop residues and low levels of soil disturbance. In conclusion, long-term conservation tillage affected the fractions and the chemical functional groups of SOM and could be ideal to preserve SOC in the Loess Plateau.

A central goal in soil microbial ecology research is to identify the biodiversity patterns and reveal the underlying mechanisms. Long-term soil acidification is known to reduce soil bacterial diversity, but the mechanisms responsible for this pattern have not been well explored. Soil acidification may reduce bacterial richness through ecological filtering (EF). In contrast, two types of processes may promote the maintenance of bacterial richness: species may adapt to the acidic pressure through evolution, and endemic species already adapted to the acidic pressure can colonize the acidified soils through dispersal. To identify the relative contribution of EF and evolution/dispersal (ED), we collected soils with a pH range of 4–7 from different ecosystems, conducted an acidification experiment with a similar pH range in a neutral soil, and proposed a conceptual framework that could distinguish the three potential types of mechanism (neither EF nor ED operate; EF operates alone; ED counteracts some effect of EF). We found that the entire bacterial domain was driven by the third type of mechanism, with ED counteracting about 42.4% (95% confidence interval: 32.7–50.4%) effect of EF. Meanwhile, different bacterial phyla/classes were governed by different types of mechanisms, and the dominant was the third type. Our results highlight the importance of both ecological and evolutionary mechanisms for regulating soil bacterial communities under environmental changes.

In many grassland ecosystems, mowing, nitrogen (N) addition, and watering are carried out to improve plant productivity for the development of livestock husbandry. However, as a result of human activities, N deposition rate is predicted to increase and precipitation is expected to change. These environmental changes affect biodiversity and ecosystem functioning, and most of the previous studies have primarily focused on their effects on macro-organisms, neglecting the responses of soil microbial communities. In this study, we examined the changes in three community attributes (abundance, richness, and composition) of the entire bacterial kingdom and 16 dominant bacterial phyla/classes in response to mowing, N addition, watering, and their combinations, by conducting a 5-year experiment in a steppe ecosystem in Inner Mongolia, China. Overall, various bacterial groups responded differentially to these experimental treatments, with Acidobacteria, Proteobacteria, Alphaproteobacteria, Deltaproteobacteria, and Gammaproteobacteria being the most sensitive. Furthermore, the treatments produced different effects, with N addition and watering having much greater effects than mowing. Addition of N primarily affected these bacterial groups by reducing soil pH, while watering affected the bacterial groups by elevating both soil water content and soil pH. As N addition and watering had contrasting effects on soil pH, they also produced counteractive effects on many bacterial groups. The counteractive effects of N addition and watering suggest that the combination of these two treatments or the concurrence of N deposition and increased precipitation may be helpful for the maintenance of soil bacterial diversity and their ecosystem functions.

Saturated fatty acids (SFAs) induce hepatocyte cell death, wherein oxidative stress is mechanistically involved. Nuclear factor (erythroid-derived 2)-like 2 (Nrf2) is a master transcriptional regulator of cellular antioxidant defense enzymes. Therefore, Nrf2 activation is regarded as an effective strategy against oxidative stress-triggered cellular damage. In this study, tert-butylhydroquinone (tBHQ), a widely used Nrf2 activator, was initially employed to investigate the potential protective role of Nrf2 activation in SFAs-induced hepatoxicity. As expected, SFAs-induced hepatocyte cell death was prevented by tBHQ in both AML-12 mouse hepatocytes and HepG2 human hepatoma cells. However, the protective effect of tBHQ is Nrf2-independent, because the siRNA-mediated Nrf2 silencing did not abrogate tBHQ-conferred protection. Alternatively, our results revealed that autophagy activation was critically involved in the protective effect of tBHQ on lipotoxicity. tBHQ induced autophagy activation and autophagy inhibitors abolished tBHQ’s protection. The induction of autophagy by tBHQ exposure was demonstrated by the increased accumulation of LC3 puncta, LC3-II conversion, and autophagic flux (LC3-II conversion in the presence of proteolysis inhibitors). Subsequent mechanistic investigation discovered that tBHQ exposure activated AMP-activated protein kinase (AMPK) and siRNA-mediated AMPK gene silencing abolished tBHQ-induced autophagy activation, indicating that AMPK is critically involved in tBHQ-triggered autophagy induction. Furthermore, our study provided evidence that tBHQ-induced autophagy activation is required for its Nrf2-activating property. Collectively, our data uncover a novel mechanism for tBHQ in protecting hepatocytes against SFAs-induced lipotoxicity. tBHQ-triggered autophagy induction contributes not only to its hepatoprotective effect, but also to its Nrf2-activating property.

Predominantly secreted by adipose tissue, adiponectin possesses insulin-sensitizing, anti-atherogenic, anti-inflammatory, and anti-angiogenic properties. Paradoxically, obesity is associated with declined plasma adiponectin levels; however, the underlying mechanisms remain elusive. In this study, we investigated the mechanistic involvement of MEK/ERK1/2 pathway in obesity-related adiponectin decrease.C57 BL/6 mice exposed to a high-fat diet (HFD) were employed as animal obesity model. Both fully-differentiated 3T3-L1 and mouse primary adipocytes were used in the in vitro experiments.Obesity and plasma adiponectin decline induced by prolonged HFD exposure were associated with suppressed ERK1/2 activation in adipose tissue. In adipocytes, specific inhibition of MEK/ERK1/2 pathway decreased intracellular and secretory adiponectin levels, whereas adiponectin gene expression was increased, suggesting that MEK/ERK1/2 inhibition may promote adiponectin protein degradation. Cycloheximide (CHX)-chase assay revealed that MEK/ERK1/2 inhibition accelerated adiponectin protein degradation, which was prevented by MG132, a potent proteasome inhibitor. Immunoprecipitation assay showed that intracellular MEK/ERK1/2 activity was negatively associated with ubiquitinated adiponectin protein levels. Consistently, long-term HFD feeing in mice increased ubiquitinated adiponectin levels in the epididymal fat pads.Adipose tissue MEK/ERK1/2 activity can differentially regulate adiponectin gene expression and protein abundance and its suppression in obesity may play a mechanistic role in obesity-related plasma adiponectin decline.

Oxidative stress plays a pathological role in the development of alcoholic liver disease. In this study, we investigated the effects of nicotinic acid (NA) supplementation on H2O2-induced cell death in hepatocytes and alcohol-induced liver injury in mice. Hepatocytes were exposed to H2O2 (0–0.4 mM) for 16 h after a 2-h pretreatment with NA (0–100 μM). Cell viability, intracellular glutathione and total NAD contents were determined. In animal experiments, male C57BL/6 mice were exposed to Lieber-De Carli liquid diet [+/− ethanol with/without NA supplementation (0.5%, w/v) for 4 weeks]. Nicotinic acid phosphoribosyltransferase (NaPRT) is the first enzyme participated in the NA metabolism, converting NA to nicotinic acid mononucleotide (NaMN). In NaPRT-expressing Hep3B cells, H2O2-induced cell death was attenuated by NA, whereas in NaPRT-lost HepG2 cells, only NaMN conferred protective effect, suggesting that NA metabolism is required for its protective action against H2O2. In Hep3B cells, NA supplementation prevented H2O2-inudced declines in intracellular total NAD and GSH/GSSG ratios. Further mechanistic investigations revealed that conservation of Akt activity contributed to NA's protective effect against H2O2-inudced cell death. In alcohol-fed mice, NA supplementation attenuated liver injury induced by chronic alcohol exposure, which was associated with alleviated hepatic lipid peroxidation and increased liver GSH concentrations. In conclusion, our findings indicate that exogenous NA supplementation may be an ideal choice for the treatment of liver diseases that involve oxidative stress.

Nitrogen deposition has dramatically altered biodiversity and ecosystem functioning on the earth; however, its effects on soil bacterial community and the underlying mechanisms of these effects have not been thoroughly examined. Changes in ecosystems caused by nitrogen deposition have traditionally been attributed to increased nitrogen content. In fact, nitrogen deposition not only leads to increased soil total N content, but also changes in the NH 4 + -N content, NO 3 − -N content and pH, as well as changes in the heterogeneity of the four indexes. The soil indexes for these four factors, their heterogeneity and even the plant community might be routes through which nitrogen deposition alters the bacterial community. Here, we describe a 6-year nitrogen addition experiment conducted in a typical steppe ecosystem to investigate the ecological mechanism by which nitrogen deposition alters bacterial abundance, diversity and composition. We found that various characteristics of the bacterial community were explained by different environmental factors. Nitrogen deposition decreased bacterial abundance that is positively related to soil pH value. In addition, nitrogen addition decreased bacterial diversity, which is negatively related to soil total N content and positively related to soil NO 3 − -N heterogeneity. Finally, nitrogen addition altered bacterial composition that is significantly related to soil NH 4 +-N content. Although nitrogen deposition significantly altered plant biomass, diversity and composition, these characteristics of plant community did not have a significant impact on processes of nitrogen deposition that led to alterations in bacterial abundance, diversity and composition. Therefore, more sensitive molecular technologies should be adopted to detect the subtle shifts of microbial community structure induced by the changes of plant community upon nitrogen deposition.

The most important challenge to use phytoremediation is how to improve its efficiency by increasing the accumulation of metals in plants, or by improving key plant biological traits that should enhance metal uptake. In this paper, we used open-top chambers to investigate the effects of elevated CO2 (860 microL L(-1)) on biomass and Cs uptake by a Sorghum vulgare x Sorghum vulgare var. sudanense hybrid and Trifolium pratense L. growing on soils spiked with various levels of cesium (0, 300, 1500 and 3000 mg Cs kg(-1)). The results showed that elevated CO2 not only increased aboveground biomass of the Sorghum and Trifolium species by 32-111%, and by 8-11%, respectively, compared to the ambient CO2 treatment, but also caused more accumulation of Cs by Sorghum species (up to 73%) than Trifolium species (up to 43%). It was speculated that the increase in biomass and the improvement in Cs accumulation ability at elevated CO2 could be related to lowered soil pH values, and changes in number and kind of microorganisms in the rhizospheres of the two tested species. This is the first report of a link among elevated CO2, increased biomass and hyperaccumulation of Cs by Sorghum and Trifolium species.

A novel Co-doped Y-shape ZnO nanostructure was fabricated using vapor–solid process. In contrast to conventional ZnO nanowires that usually grow along c -axis, the branches of the single-crystalline Y-shaped nanostructure grew along directions that deviated significantly from the c -axis for 22∘,96∘, and 13∘, respectively. Transport measurement showed that the Y-shape nanostructure can function as a switch. Due to possible ordered substitution of Zn by Co, ferromagnetism was observed at 300 K and even 400 K, suggesting its potential application as an excellent dilute magnetic semiconductor nanomaterial.