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Arsenic and cadmium pose a potential health risk to human beings via rice grain consumption. In the current study, a pot experiment was conducted to evaluate the effect of Br (5 mM and 20 mM) and Se (1 mM) at rice tillering and filling stages on Cd and As accumulation in rice grain and their health risk indices. The results showed that Br or Se applications at different stages of rice improved the photosynthesis, reduce MDA content in flag leaves by 17.41%–38.65%, increased rice biomass and grain yield by 10.50%–29.94% and 10.50%–36.56%, and enhanced grain N and P uptake by 3.25%–34.90%, and 22.98%-72.05%, respectively. Applications of Br and Se effectively decreased Cd and As concentration in rice grain by 31.74%–86.97% and 16.42%–81.13% respectively. Compared to the individual treatment, combined 20 mM Br and 1 mM Se at the filling stage showed the lowest accumulation of As (0.149 mg·kg−1) and Cd (0.105 mg·kg−1) in grain, and its health risk index was below the acceptable limits (HRI < 1). This implies that application of Br and Se at the filling stage is a promising strategy for the safe production of rice in As and Cd co-contaminated regions. In this study, foliar applications of Br and Se at the grain filling and tillering stage demonstrate their effect on As and Cd accumulation. The findings showed that Br and Se resulted in the Se concentration in grains reaching the Se-enriched level, and the accumulation of As and Cd was the lowest. Furthermore, the application of Br and Se decreased lipid peroxidation, promoted N and P uptake, and increased the rate of photosynthesis in the rice plants, which resulted in increasing rice growth and grain yield. The HRI of heavy metals was below the acceptable limits after application of Br and Se.

Soil Cadmium (Cd) contamination has become a severe environmental problem around the world. Kenaf has great potential for utilization and phytoremediation of soil contaminated with heavy metal. Arbuscular mycorrhizal fungi (AMF) can help plants alleviate Cd stress, but the underlying mechanism remains completely unknown. In this study, kenaf was inoculated or not inoculated with AMF at cadmium concentrations of 10 mg kg

The developments in the high-power densities and high integration of electronic devices have put forward higher requirements for advanced thermal management materials (TMMs) to meet the rising dema...

Petroleum spills and land contamination are becoming increasingly common around the world. Polycyclic aromatic hydrocarbons (PAHs) and other pollutants found in petroleum are constantly migrating underground, making their migration in soil a hot research topic. Therefore, it is of great significance to evaluate the migratory process of petroleum hydrocarbons in petroleum-polluted soil to clarify its ecological and environmental risks. In this study, Phenanthrene (PHE) was used as a typical pollutant of PAHs. The soil was gathered from three typical oilfields in China, and a soil column apparatus was built to simulate the vertical migration of PHE in the soil. The migration law and penetration effect of PHE in various environmental conditions of soil were investigated by varying the ionic strength (IS), pH, particle size, and type of soil. According to the literature, pH has no discernible effect on the migration of PHE. The migration of PHE was adversely and positively linked with changes in IS and soil particle size, respectively. The influence of soil type was mainly manifested in the difference of organic matter and clay content. In the Yanchang Oilfield (YC) soil with the largest soil particle size and the least clay content, the mobility of PHE was the highest. This study may reveal the migration law of PAHs in soils around typical oilfields, establish a new foundation for PAH migration in the soil, and also provide new ideas for the management and control of petroleum pollution in the soil and groundwater.

The combination of pump-and-treat and in situ chemical oxidation processes can effectively accelerate the remediation of DNAPL pollutant in groundwater.

1,2-Dichloroethane (1,2-DCA) is a common compound found in groundwater contaminated with organics. This compound is difficult to remove from groundwater and has the potential to inflict significant harm on human health and the environment. This study used sodium persulfate (Na

Nonylphenol (Noph) has garnered worldwide concern as a typical endocrine disruptor due to its toxicity, estrogenic properties, and widespread contamination. To better elucidate the interaction of Noph with ubiquitously existing microplastics (MPs) and the potential interdependence of their transport behaviors, batch adsorption and column experiments were conducted, paired with mathematical modeling. Compared with sand, MPs and soil colloids show stronger adsorption affinity for Noph due to the formation of hydrogen bonding and the larger numbers of interaction sites that are available on solid surfaces. Limited amount of soil-colloid coating on sand grains significantly influenced transport behaviors and the sensitivity to solution chemistry. These coatings led to a monotonic increase in Noph retention and a nonmonotonic MPs retention in single systems because of the altered physicochemical properties. The mobility of both MPs and Noph was enhanced when they coexisted, resulting from their association, increased electrostatic repulsion, and competition on retention sites. Limited release of MPs and Noph (under reduced ionic strength (IS) and increased pH) indicated strong interactions in irreversible retention. The retention and release of Noph were independent of IS and solution pH. A one-site model with a blocking term and a two-site kinetic model well described the transport of MPs and Noph, respectively. Our findings highlight the essential roles of coexisting MPs and Noph on their transport behaviors, depending on their concentrations, IS, and physicochemical properties of the porous media. The new knowledge from this study refreshes our understanding of the co-transport of MPs and organic contaminants such as Noph in the subsurface.

Global production and use of plastics have resulted in the wide dissemination of micro- and nano-plastics (MNPs) to the natural environment. Potentially acting as a vector, the role of MNPs on the fate and transport of environmental pollutants (e.g., antibiotic s such as chlortetracycline hydrochloride; CTC) has garnered global concern recently. Herein, the cotransport of MNPs and CTC in columns packed with uncoated sand or soil colloid-coated sand (SCCS) under different degrees of physicochemical heterogeneity and ionic strength was systematically explored. Our results show that MNPs and CTC inhibit the transport of each other when they coexist. The adsorption of CTC onto sand grains, MNPs, and soil colloids, as well as the aggregation of MNPs in the presence of CTC could be the major contributors to the enhanced retention of CTC and MNPs. In SCCS with different degrees of soil colloid coating, the adsorption of CTC on soil colloids is critical to influence the transport of CTC, and the nonlinear retention of MNPs to soil colloids is mainly attributed to the alteration of collector surface roughness by soil colloids. High ionic strength slightly facilitates CTC transport due to the competition for adsorption sites and the formation of CTC macromolecules, but significantly inhibits MNPs transport by suppressing the electrostatic double layers based on colloid stability theory. Consequently, the cotransport of MNPs and CTC is governed by the coupled interplay of collector surface roughness and chemical heterogeneity, due to the soil colloid coatings and the adsorbed CTC on the surfaces associated with solution chemistries such as ionic strength. Increased cotransport of MNPs and CTC occurred under a higher concentration of MNPs due to a larger number of adsorption sites for CTC. Our findings advance the current understanding of the complex cotransport of MNPs and antibiotic s in the environment. This information is valuable for understanding contaminant fate and formulating strategies for environmental remediation due to contamination of MNPs and co-occurring contaminants.

The intermediate sulfur species of pyrite chemical and biological oxidation have been the subject of controversy for some time, especially the question of whether or not elemental sulfur (S 0 ) and polythionates (S n O 6 2 − ) are formed during the oxidation process. Acidithiobacillus ferrooxidans ( A . ferrooxidans ), one of the most common sulfur-oxidizing bacterial strains, has been shown to remarkably accelerate pyrite oxidation. In this study, the intermediate products of pyrite oxidation with and without A . ferrooxidans present were compared by employing different analytical techniques; i.e., high performance liquid chromatography (HPLC), X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) with energy dispersive spectrometer (EDS). The HPLC results showed that the concentrations of S 0 , S 3 O 6 2 − , S 4 O 6 2 − , S 5 O 6 2 − and S 6 O 6 2 − increased during pyrite oxidation process in the presence of A . ferrooxidans . Secondary minerals jarosite (KFe 3 (SO 4 ) 2 (OH) 6 ) and iron(III) oxide-hydroxide (FeOOH) were also detected by XRD and XPS. Without A . ferrooxidans , S 0 was also formed and along with S 3 O 6 2 − , S 4 O 6 2 − and S 5 O 6 2 − but only at very low concentrations at the end of the experiment. SEM micrographs further revealed that the pyrite was severely eroded by A . ferrooxidans and some spheroidal particles covered the surfaces of pyrite residues. These particles are most likely to be KFe 3 (SO 4 ) 2 (OH) 6 based on EDS analysis. The present study has quantitatively confirmed the presence of intermediate products of S 0 and S n O 6 2 − during pyrite oxidation, information that deepens our understanding of the mechanism of pyrite oxidation.

A new SCR with the variation lateral base doping (VLBD) structure (VSCR) is proposed to improve the turn-on speed for electrostatic discharge (ESD) protection. The turn-on speed of the SCR was determined mainly by the base transit time of the parasitic p-n-p and n-p-n transistors of the SCR, and the VLBD structure can reduce the base transit time of the bipolar transistors to improve the turn-on speed of the SCR. The experimental and simulation results show that the turn-on time of the VSCRs with the VLBD structure is 12% less than that of the MLSCR with the traditional uniform base doping without adding extra process masks and increasing the chip area.

Recent investigations have shown frequent detection of pharmaceuticals in soils and waters posing potential risks to human and ecological health. Here, we report the enhanced removal of tylosin (TYL) from water by a novel goethite biochar (BCF) composite. Characterization by scanning electron microscopy (SEM) images showed good dispersion of goethite nanoparticles on the biochar surface. The coating was constructed by well-crystallized cubic phase goethite nanoparticles as examined by Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) analysis. To evaluate the feasibility of BCF composite as a potential adsorbent for antibiotic removal, batch sorption experiments were conducted using TYL as the model antibiotic molecule. The results showed that this adsorbent showed rapid and high sorption of TYL. According to the Henry and Freundlich model, the maximum capacities of TYL on BCF were 8132.89 L/kg and 5386.76 (μg/g)/(mg/L) n respectively. Besides, the sorption capacity of TYL on BCF was obviously affected by pH and ionic strength. The sorption mechanisms of TYL on BCF were contributed to hydrophobic, electrostatic, H-bonding, cation exchange and π-π EDA interaction. The present work suggests that BCF composite, owing to their simple preparation procedures, high sorption capacity, low cost, and environmentally benign nature, have great potential as the next-generation adsorbent in the removal of antibiotics and other emerging contaminants.

Surfactant-enhanced phytoremediation is a green technology for the treatment of contaminated soil. In a pot experiment, two biosurfactants (rhamnolipid and soybean lecithin) and a synthetic surfactant (Tween 80) were used to facilitate phytoremediation of crude oil contaminated soil by maize (Zea mays. L). Results showed that these surfactants did not significantly affect the biomass production of maize, but they inhibited the chlorophyll fluorescence of the maize leaf. Rhamnolipid and soybean lecithin enhanced the soil microbial population, resulting in increased removal of total petroleum hydrocarbons from the soil. Saturated hydrocarbons were the main component of petroleum hydrocarbons decreased in the soil. In addition, the accumulation of polycyclic aromatic hydrocarbons was inhibited in the maize leaf by all selected surfactant treatments, but was facilitated in maize root by the treatments of rhamnolipid and Tween 80. This work indicates that biosurfactant amended phytoremediation may be a useful biotechnological approach for the remediation of petroleum hydrocarbon polluted soil.

The degradation of pyrene (PYR) by Mycobacterium gilvum immobilized on peanut shell powder (PSP) was improved by chemically modifying the PSP. The physicochemical properties of the modified biomass (M-PSP) were characterized with surface area analysis, X-ray diffraction, Fourier transform infrared and solid-state CP/MAS 13C NMR spectra. The results showed that the chemical modification decreased the crystallinity of the biomass and destroyed the benzene rings in the cellulose, which improved the porosity of PSP. Fluorescein diacetate activity (FDA) of cells immobilized on the M-PSP decreased more slowly than cells immobilized on PSP. The PYR degradation efficiencies achieved by bacteria immobilized on M-PSP was higher than that achieved by immobilized bacteria on PSP after 7 d. It revealed that chemical modification of biomass could further improve bacterial activity and enhance the degradation ability of the cells compared with the raw one, as we expected. In summary, this study shows that M-PSP is a good immobilizing bio-mass for supporting pollutant-degrading bacteria and could be employed as an effective material for PYR biodegradation.

Cell immobilization technology has been considered as an effective method for bioremediation of hydrocarbon-contaminated soil. However, bacteria immobilized by a single method often encounter some problems, e.g., cell leakage, cellular damage and no reproduction. In this study, a biomimetic hybrid material was constructed by pre-immobilization of bacteria on sawdust followed by coating a silica layer through vapor deposition (Silica-IC). The viability and metabolic activity of Silica-IC were investigated. Results showed that the silica layer covering the bacterial agent could significantly reduce cell leakage from sawdust without losing reproductive capacity on nutrient plates. A viability assay by SYTO9/PI in flow cytometry indicated that the proportion of live cells was decreased 30% and injured cells was increased 23.9%, while that of dead cells was still below 2.5% during storage at 4 °C for 15 days, i.e., membrane permeability of Silica-IC was increased, indicating bacterial cells in Silica-IC were able to maintain long-term storage stability and shelf life. The metabolic activity of Silica-IC toward phenanthrene (Phe) was enhanced both in liquid and soil. Phe degradation kinetics of Silica-IC in liquid medium well fitted an adsorption–degradation model, suggesting that the silica layer did not inhibit Phe diffusion. Moreover, the Phe removal percentage of Silica-IC in soil was up to 93.4% on day 2. Silica-IC in soil grew well and the growth was closely related to the residual amount of Phe. This work provides a route to develop a wide range of bio-materials for bioremediation.

This study reports on the enhanced bioremediation of pyrene (PYR)-contaminated soil resulting from organisms immobilized in layer-by-layer (LBL) assembled microcapsules. The characterization by microscopy indicated that the shape of the microcapsule was like a flake with a diameter of 3–4 μm and that bacteria were encapsulated in the microcapsules. Soil remediation experiments revealed that PYR with an initial concentration of 100 mg kg−1 in dry soil could be 81% removed by an immobilized consortium (107 CFU g−1 in dry soil) in 40 days, while only 42% was removed by the free bacteria. Moreover, the LBL-immobilized cells could cause a significant increase in the biodiversity of the bacterial community, soil enzyme activity and the number of PYR-degrading bacteria in the soil, successfully accounting for accelerated PYR removal. Illumina MiSeq sequencing results showed that Proteobacteria and Actinobacteria were observed as the predominant groups during bioremediation in the LBL groups. The active uncultured bacteria belonged to Xanthomonadaceae, Planococcaceae, Pseudomonas, Mycobacterium, Sphingomonadaceae, Acinetobacter, Flavobacterium, Comamonadaceae, Bacillus, Sphingobacterium, Enterobacteriaceae, and Streptomyces, the latter two classes having rarely been associated with PAH-degrading activity. The results indicated that the LBL microcapsule treatment might be a potential bacteria immobilization option for soil bioremediation.

The present study assessed the expression of solute carrier 6 member 1 (SLC6A1) in ovarian cancer (OC) tissues and evaluated the effect of silencing SLC6A1 or caudal type homeobox 2 (CDX2) on the proliferation, migration, and invasion of SK-OV-3 OC cells. The levels of caudal type homeobox 2 (CDX2) and SLC6A1 mRNA were also examined in OC SK-OV-3, OVCAR3 and A2780 cell lines. The mRNA levels of CDX2 and SLC6A1 in SK-OV-3 OC cells were assessed following transection with microRNA (miR) 133a mimics; the mRNA and protein levels of SLC6A1 were determined following the silencing of CDX2, and the mRNA expression of CDX2 was gauged following the silencing of SLC6A1. A luciferase reporter assay was performed to assess the effect of miR133a on the CDX2 and SLC6A1 3'-untranslated regions (3'UTRs). The proliferation, migration and invasion rate of SK-OV-3 cells were then examined following the silencing of CDX2 or SLC6A1. The expression of SLC6A1 was increased in OC compared with adjacent tissue. The expression of CDX2 and SLC6A1 in SK-OV-3 and OVCAR3 cells was increased compared with A2780 cells (P

A pot experiment was conducted to investigate the effects of pollination on cadmium (Cd) phytoextraction from soil by mature maize plants. The results showed that the unpollinated maize plants accumulated 50% more Cd than that of the pollinated plants, even though the dry weight of the former plants was 15% less than that of the latter plants. The Cd accumulation in root and leaf of the unpollinated maize plant was 0.47 and 0.89 times higher than that of the pollinated plant, respectively. The Cd concentration in the cob was significantly decreased because of pollination. Preventing pollination is a promising approach for enhancing the effectiveness of phytoextraction in Cd-contaminated soils by maize. This study suggested that in low Cd-contaminated soil pollination should be encouraged because accumulation of Cd in maize grains is very little and maize seeds can bring farmers economic benefits, while in high Cd-contaminated soil, inhibition of pollination can be applied to enhance phytoextraction of Cd from soil by maize plant.

Surfactant-enhanced remediation (SER) is considered as a promising and efficient remediation approach. This review summarizes and discusses main drivers on the application of SER in removing polycyclic aromatic hydrocarbons (PAHs) from contaminated soil and water. The effect of PAH-PAH interactions on SER efficiency is, for the first time, illustrated in an SER review. Interactions between mixed PAHs could enhance, decrease, or have no impact on surfactants' solubilization power towards PAHs, thus affecting the optimal usage of surfactants for SER. Although SER can transfer PAHs from soil/non-aqueous phase liquids to the aqueous phase, the harmful impact of PAHs still exists. To decrease the level of PAHs in SER solutions, a series of SER-based integrated cleanup technologies have been developed including surfactant-enhanced bioremediation (SEBR), surfactant-enhanced phytoremediation (SEPR) and SER-advanced oxidation processes (SER-AOPs). In this review, the general considerations and corresponding applications of the integrated cleanup technologies are summarized and discussed. Compared with SER-AOPs, SEBR and SEPR need less operation cost, yet require more treatment time. To successfully achieve the field application of surfactant-based technologies, massive production of the cost-effective green surfactants (i.e. biosurfactants) and comprehensive evaluation of the drivers and the global cost of SER-based cleanup technologies need to be performed in the future.

Nanoscience is a grand and wide science, and there are many kinds of nanomaterials. In this paper nanomaterials are divided into three: the naturial nanocrystals, the artificial nano structural materials and the functional polymer materials. Carbon nanotechnologies which are in the fast-development areas are reviewed in detail including their structural features, opto-electronic properties and its applications used as optoelectronic devices. And the graphene are introduced in detail. Especially emphasize is put on the the carbon nanotechnology development and its importance.

Maize is an economic crop that is also a candidate for use in phytoremediation in low-to-moderately Cd-contaminated soils, because the plant can accumulate high concentration of Cd in parts that are nonedible to humans while accumulating only a low concentration of Cd in the fruit. Maize cultivars CT38 and HZ were planted in field soils contaminated with Cd and nitrilotriacetic acid (NTA) was used to enhance the phytoextractive effect of the maize. Different organs of the plant were analyzed to identify the Cd sinks in the maize. A distinction was made between leaf sheath tissue and leaf lamina tissue. Cd concentrations decreased in the tissues in the following order: sheath > root > lamina > stem > fruit. The addition of NTA increased the amount of Cd absorbed but left the relative distribution of the metal among the plant organs essentially unchanged. The Cd in the fruit of maize was below the Chinese government’s permitted concentration in coarse cereals. Therefore, this study shows that it is possible to conduct maize phytoremediation of Cd-contaminated soil while, at the same time, harvesting a crop, for subsequent consumption.

Detection efficiency is one of the key parameters that affect the performance of gated-mode avalanche photodiodes in quantum key distribution. In this paper, the impact of the waveform of faint picosecond laser pulses on detection efficiency is investigated both experimentally and analytically. Two kinds of laser pulses are attenuated to the single photon level to measure and plot single photon detection efficiency versus synchronous delay between the detector and the laser source. The results show that the narrower laser pulse with single peak can be detected with about 9% higher detection efficiency and lead to a lower QBER than the pulse with subpeak and a broadened pedestal.

The stem cell factor receptor (c-Kit) has been known to play critical roles in regulating numerous aspects of cellular behavior including cell growth, differentiation, migration and metabolism. In this investigation, a three-dimensional pharmacophore model of c-Kit inhibitors has been established by using the HypoGen algorithms implemented in the catalyst software package. The best quantitative pharmacophore model, hypothesis 1, which has the highest correlation coefficient (0.989), consists of one hydrogen bond acceptor, two hydrogen bond donors and one hydrophobic feature. To our knowledge, this is the first report on the pharmacophore modeling study of c-Kit inhibitors. The best hypothesis, hypothesis 1, was used to screen molecular structural databases, including Specs and China Natural Products Database for potential lead compounds. The hit compounds were subsequently subjected to filtering by Lipinski's rules and docking study to refine the retrieved hits and as a result to reduce the rate of false positive. Finally 28 compounds were purchased or synthesized for further in vitro assay against several human tumour cell lines including A549, MCF-7, HepG2 and PC-3, in which c-Kit is overexpressed. Two compounds show very low micromolar inhibition potency against the PC-3 and HepG2 cell lines respectively. And they were selected for further modification and testing.

A passive quench circuit is used to study the punch-through characters of avalanche photodiodes under the Geiger mode. The photocurrent–voltage curve indicated clearly the punch-through voltage while the dark current–voltage curve is insensitive to the punch-through. The experiments demonstrate different distributions of the carries. The dark carriers counts increase much faster than the photo-carriers counts due to the different collection efficiency. A proper selection of the bias can increase the signal-to-noise ratio (SNR) of the single photon detector.

We demonstrate experimentally an intrinsically stable polarization coding and decoding system composed of optical-fiber Sagnac interferometers with integrated phase modulators for quantum key distribution. An interference visibility of 98.35% can be kept longtime during the experiment without any efforts of active compensation for coding all four desired polarization states.

Water temperature, dissolved oxygen (DO), pH, and specific conductivity (spc) were measured in a time interval of 15 min in a karst spring and the spring-fed pool with flourishing submerged plants in Guilin, SW China under dry weather for periods of 2 days. Measurements allowed calculation of calcium and bicarbonate concentrations ([Ca2+] and [HCO3 −]), and thus CO2 partial pressure ( $$ P_{{{\text{CO}}_{2} }} $$ ) and saturation index of calcite (SIc). Results show that there were not any diurnal variations in the physico-chemical parameters of the water for the spring. However, during daytime periods, pool water $$ P_{{{\text{CO}}_{2} }} $$ decreased to far less than the spring water in a few hours, pH and SIc increased to greater than the spring, and [Ca2+] and [HCO3 −] decreased to less than the spring. During nighttime periods, pool water $$ P_{{{\text{CO}}_{2} }} $$ returned to or even increased to greater than the spring, pH and SIc decreased to less than the spring, and [Ca2+] and [HCO3 −] increased to greater than the spring. The decrease in [Ca2+] and [HCO3 −] to less than the spring during daytime periods implies daytime deposition of calcium carbonate, while the increase in [Ca2+] and [HCO3 −] to greater than the spring during nighttime periods implies nighttime dissolution of calcium carbonate. The direction of the observed changes depended essentially on the illumination, indicating that daytime photosynthetic and nighttime respiratory activities in the pool aquatic plant ecosystem, which were further evidenced by the increase and decrease in DO during daytime and nighttime periods respectively, were the main processes involved. The large variations of the components of the carbonate system imply considerable changes of the capacities of CO2 and O2 in water. The finding has implications for water sampling strategy in slow-flowing karst streams and other similar environments with stagnant water bodies such as estuaries, lakes, reservoirs, and wetlands, where aquatic plant ecosystem may flourish.

Error reconciliation is a necessary step for quantum key distribution process. In this paper, the correction ability of error reconciliation procedure which is called Winnow protocol is analyzed and estimated, moreover, it gives some expressions about it. The experiment results proved the capability of Winnow protocol are excellent. It is also indicates that the smallest N has the most correction efficiency where from the communication times between the legitimate parties and the data remaining efficiency consideration.

This paper proposes a method of acoustic vehicle classification. We extract acoustic feature of wheeled vehicle and track vehicle based on the optimum wavelet packet energy and classify these two types of vehicle based on the fuzzy classifier. For evaluation purposes, real data are used from DARPA's SensIT project. The experiment results show that the proposed method can improve the correct recognition rate, and achieve the balance between the processing time and performance.

This study has investigated the use of screened maize for remediation of soil contaminated with crude oil. Pots experiment was carried out for 60 days by transplanting maize seedlings into spiked soils. The results showed that certain amount of crude oil in soil (≤2 147 mg·kg(-1)) could enhance the production of shoot biomass of maize. Higher concentration (6 373 mg·kg(-1)) did not significantly inhibit the growth of plant maize (including shoot and root). Analysis of plant shoot by GC-MS showed that low molecular weight polycyclic aromatic hydrocarbons (PAHs) were detected in maize tissues, but PAHs concentration in the plant did not increase with higher concentration of crude oil in soil. The reduction of total petroleum hydrocarbon in planted soil was up to 52.21-72.84%, while that of the corresponding controls was only 25.85-34.22% in two months. In addition, data from physiological and biochemical indexes demonstrated a favorable adaptability of maize to crude oil pollution stress. This study suggested that the use of maize (Zea mays L.) was a good choice for remediation of soil contaminated with petroleum within a certain range of concentrations.

A pot experiment was conducted to investigate the effects of pollination on cadmium (Cd) phytoextraction from soil by mature maize plants. The results showed that the unpollinated maize plants accumulated 50% more Cd than that of the pollinated plants, even though the dry weight of the former plants was 15% less than that of the latter plants. The Cd accumulation in root and leaf of the unpollinated maize plant was 0.47 and 0.89 times higher than that of the pollinated plant, respectively. The Cd concentration in the cob was significantly decreased because of pollination. Preventing pollination is a promising approach for enhancing the effectiveness of phytoextraction in Cd-contaminated soils by maize. This study suggested that in low Cd-contaminated soil pollination should be encouraged because accumulation of Cd in maize grains is very little and maize seeds can bring farmers economic benefits, while in high Cd-contaminated soil, inhibition of pollination can be applied to enhance phytoextraction of Cd from soil by maize plant.

We present implementation of quantum cryptography with polarization code by wave-guide type phase modulator. At four different low input voltages of the phase modulator, coder encodes pulses into four different polarization states, 45°, 135° linearly polarized or right, left circle polarized, while the decoder serves as the complementary polarizers.

Diurnal variations of hydrochemistry were monitored at a spring and two pools in a travertine-depositing stream at Baishuitai, Yunnan, SW China. Water temperature, pH and specific conductivity were measured in intervals of 5 and 30 min for periods of 1 to 2 days. From these data the concentrations of Ca 2+ , HCO3 ) , calcite saturation index, and CO2 partial pressure were derived. The measurements in the spring of the stream did not show any diurnal variations in the chemical composition of the water. Diurnal variations, however, were observed in the water of the two travertine pools downstream. In one of them, a rise in temperature (thus more CO2 degassing) during day time and consumption of CO2 due to photosynthesis of submerged aquatic plants accelerated deposition of calcite, whereas in the other pool, where aquatic plants flourished and grew out of the water (so photosynthesis was taking place in the atmosphere), the authors suggest that temperature-dependent root respiration underwater took place, which dominated until noon. Consequently, due to the release of CO2 by the root respiration into water, which dominated CO2 production by degassing induced by temperature increase, the increased dissolution of calcite was observed. This is the first time anywhere at least in China that the effect of root respiration on diurnal hydrochemical variations has been observed. The finding has implications for sampling strategy within travertine-depositing streams and other similar environments with stagnant water bodies such as estuaries, lakes, reservoirs, pools and wetlands, where aquatic plants may flourish and grow out of water.

The surface morphology of GaInP buffer layers mismatched to GaAs substrate is probed to study its impact on the distribution of self-organized InP island. The steps, facet island matrix and mismatch dislocations formed sequentially as Ga content increased in buffer layers. And the lateral distribution of InP island can be controlled efficiently by the steps, island matrix and mismatch dislocation. The island matrix, with about 100nm periodicity, is found to be efficient to obtain InP island lateral distribution with 1μm periodicity on sample 3. The result also shows the dislocation had different functions to control the island distribution along different directions, [110] and [ 1 1 ¯ 0 ] directions.

The self-organized InP islands grown on GaInP buffer layers mismatched to GaAs substrate were utilized to find the influence of the stress between the buffer layers and the islands on the shape of the islands and its distribution. The shape of the islands was elongated with the increasing stress. The self-organized islands at the surface of buffer layers were analyzed by scaling theories to show a periodical distribution. Some kinds of buffer layers such as the mismatched GaInP on the GaAs (1 0 0) tilt to (1 1 1) 15° can improve the periodicity of the island separation distribution.

Understanding the uptake of organic pollutants by plants is an important part of the assessment of risks from crops grown on contaminated soils. This study was an investigation of the effects of surfactants added to PAHs-contaminated soil on the uptake and accumulation of PAHs in maize tissues during phytoremediation. The accumulation of phenanthrene (PHE) and pyrene (PYR) by maize plant was not influenced significantly by the surfactant amendment to the soil. The distribution of PHE and PYR in maize tissues was not positively correlated with the corresponding lipid contents. Remarkably, the concentrations of PHE (20.9 ng g(-1)) and PYR (0.9 ng g(-1)) in maize grain were similar to or even much lower than those in some foods. Moreover, surfactants could enhance the removal of pollutants from contaminated soil during phytoremediation, which might be due to surfactant desorption ability and microbial activity in soil. The study suggests that use of maize plant with surfactant is an alternative technology for remediation of PAHs-contaminated soils.

The nonlinear Schroedinger equation (NLSE) in erbium-doped fiber (EDF) is obtained. Based on this NLSE, a more generalized form of the propagation equation in the erbium-doped fiber amplifiers (EDFA) is given which has included the phase shift that the erbium ions induce. The cross-phase modulation (XPM) in the EDFA is studied according to that erbium ions induced phase shift. An analytical expression is given to the frequency chirp that the doped-erbium ions induce. It was found that the frequency chirp dose not change much with the wavelength except at the neighbouring wavelengths (around 1.531 μm) where absorption and the emission cross-sections of the erbium ions reach their maximum, and the frequency chirp has opposite sign on the two sides around 1.531 μm. Furthermore, it was found that the frequency chirp will increase with increasing length of the EDF.

A simple strain method is used to change uniform gratings into chirped gratings. The correspondent theory is presented. It is deduced that the product of the maximum bandwidth and the corresponding dispersion is nearly equal to a constant. The dispersion compensation distance for standard single-mode fiber G.652,10 Gb/s systems over 100 km is realized by using this method.

Nonlinear chirped gratings are numerically demonstrated to have a direction-dependent switching behavior. For the two incident directions, bistability exists with different switching-on powers, and the instable high transmissivity states have different critical powers. The direction-dependent bistability is due to the difference of the energy contained in the gratings for the two incident directions; the direction-dependent critical powers for instability origin from the different modulation instability threshold. Furthermore, it is first reported that for instable output there are spectral side lobes whose frequency shifts relative to carrier frequency have jumps at some input powers.

Chirped gratings with uniform Kerr nonlinearity are numerically demonstrated to have direction-dependent switching behavior, which is caused by the different energy storage between the two incident directions. This effect can find useful applications such as optical diode and optical switch-isolator.

We present a high-speed polarization-coding method, which makes use of phase modulation, for use in a quantum key distribution (QKD) system. This technique has been introduced into a QKD system for the first time. A completely quantum mechanical method is employed to describe quantum information processing here. Experiments on a balanced element for polarization coding by phase modulation are described in detail. The experimental results demonstrate that this technique can encode or decode polarization at high speed (with feasibility in the GHz range) and low voltage (a few volts) successfully.

By means of the multiscale singular perturbation method and directly from the Maxwell vector wave equation containing the nonlinear polarization term, we have obtained two kinds of equations describing the propagation of nonlinear sub-picosecond optical pulse in optical fibers. These two equations are the nonlinear Schrodinger equations with different linear combinations of the higher order terms (the higher order dispersion term, the self-steepening term, and the delayed nonlinear response term). The approximate coefficients of the equations are derived under the weakly guiding condition. Using a perturbation method, we show that these two equations share a solitary wave solution.