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The paper analyzes the film sticking technology and stress of large-span single-layer spherical reticulated shell structure,uses SolidWorks,a three-dimensional software,to simply model the large-span single-layer spherical reticulated shell structure, analyzes the stress of triangle frame after filming by theoretical analysis and ANSYS simulation software.In the research, the experimenter makes one kind of film cutting device plate used for triangle frame.The film cutting by film cutting device plate not only can save cost and reduce labor intensity during sticking film,but also position the film accurately and improves the overall stiffness of the spherical reticulated shell.By analyzing the real stress situation in the actual operation process of large-span reticulated shell structure,the mechanical loading test was used to analyze the overall mechanical properties of the spherical reticulated shell structure before and after film sticking,and verified that the overall mechanical properties and stiffness of large-span reticulated shell structure are improved after film sticking by using film cutting device is used.The test analyses are basically consistent with the simulation analyses,which further verifies the feasibility of the film cutting device and the rationality of the design of large-span reticulated shell structure,which provides a reference for the further design of large-span reticulated shell structure.

Naphthenic acid (NA), a new kind of toxic pollutants, is labeled as the potential threat to human health. However, the transformations of NAs in marine environments are still unclear. In this study, the characteristics and pathways of cyclohexylcarboxylic acid (CHCA) biodegradation were explored in the presence of nitrate. Results showed that CHCA was completely degraded with pseudo-first-order kinetic reaction under aerobic and anaerobic conditions, accompanied by nitrate removal rates exceeding 70%, which was positively correlated with CHCA degradation(P

Domoic acid (DA) is a harmful algal toxin produced by marine diatom Pseudo-nitzschia and seriously threatens ecosystem and human health. However, the current knowledge on its biotransformation behavior in coastal anaerobic environment is lacking. This study investigated the anaerobic biotransformation of DA by a new marine consortium GH1. The results demonstrated that 90% of DA (1 mg L

The relationships between denitrifying microbial communities and their controlling factors are largely unknown in eutrophic estuaries sediment. This work showed that in Liaohe Estuary, nirS-type de...

This study investigated differences in the community structure and environmental responses of the bacterial community in sediments of the Bohai Sea. Illumina high-throughput sequencing technology and real-time PCR were used to assay the bacterial 16S rRNA genes in the surface sediments of 13 sampling stations in the Bohai Sea. The results showed that sediments at the majority of the 13 sampling stations were contaminated by heavy metal mercury. The main phyla of bacteria recorded included Proteobacteria (52.92%), Bacteroidetes (11.76%), Planctomycetes (7.39%), Acidobacteria (6.53%) and Chloroflexi (4.97%). The genus with the highest relative abundance was Desulfobulbus (4.99%), which was the dominant genus at most sampling stations, followed by Lutimonas and Halioglobus. The main factors influencing bacterial community structure were total organic carbon, followed by depth and total phosphorus. The content of lead, cadmium, chromium, copper and zinc had a consistent effect on community structure. Arsenic showed a negative correlation with bacterial community structure in most samples, while the impact of mercury on community structure was not significant. The bacterial community in sediment samples from the Bohai Sea was rich in diversity and displayed an increase in diversity from high to low latitudes. The data indicated that the Bohai Sea had abundant microbial resources and was rich in bacteria with the potential to metabolize many types of pollutants.

Although previous studies have analyzed bacterial diversity and community composition in marine ecosystems, some focused on the relationship between pathogenic bacteria and the composition of bacterial communities in sewage outfalls. The interactions between four pathogenic bacteria (E. coli, Enterococcus, Staphylococcus aureus, fecal coliforms) isolated from the sewage outfall and the bacterial diversity were investigated in the sea adjacent to the Xinghai sewage outlet, China to illustrate the influence of pathogenic bacteria on the bacterial community structure. Higher bacterial diversity was observed in the sewage outlet, and the abundance of pathogenic bacteria and bacterial diversity generally decreased with the increase in the distance from the sewage outlet. Bacterial community structure was mainly influenced by water temperature, conductivity, and dissolved oxygen in summer and winter, while pH, Oxidation-Reduction Potential and salinity were the main factors in autumn. The bacterial abundance had the most significant correlation with E. coli, followed by Enterococcus and fecal coliforms, and the least with Staphylococcus aureus. E. coli (-0.76 < r < 0.79) and Enterococcus (-0.88 < r < 0.77) had similar correlations to the same bacteria, in contrast to Staphylococcus aureus (-0.62 < r < 0.63). The above suggested that pathogenic bacteria may affect the bacterial community structure in the sea adjacent to the sewage outlet besides environmental factors.

Residual levels and accumulation characteristics of six hazardous heavy metal elements (As, Cd, Hg, Tl, Pb, and U) and seven essential heavy metal elements (Cr, Mn, Fe, Ni, Cu, Zn, and Se) were investigated in 17 kinds of frequently consumed foodstuffs collected from 33 cities distributed in five regions of China. The concentrations of the detected metals were lower than the maximum limits promulgated by the Chinese government except Pb and inorganic As (iAs). Foods of aquatic origin and terrestrial plant origin exhibited high potentials to accumulate heavy metals, especially algae and shellfish. The calculated hazard index (HI) of heavy metal exposure via consumption of foodstuffs were 2.93-5.01 for adults in the five surveyed region, implying the co-exposure of heavy metals via food consumption would lead to potential non-carcinogenic risks. iAs was the predominant contributor to HI values with the average contribution of 40.5% in all five regions. Consumption of terrestrial plant origin foods contributed 76.9% of HI values induced by heavy metal exposure. The calculated target cancer risks of iAs in the five regions were 5 × 10

Staphylococcus aureus possesses an extraordinary ability to deal with a wide range of osmotic pressure. To performed transcriptomic and metabolomic analyses on the potential mechanism of gradient salinity stress adaptation in S. aureus ZS01. The results revealed that CPS biosynthetic protein genes were candidate target genes for directly regulating the phenotypic changes of biofilm. Inositol phosphate metabolism was downregulated to reduce the conversion of functional molecules. Gluconeogenesis pathway was downregulated to reduce the production of endogenous glucose. Pyruvate metabolism pathway was upregulated to promote the accumulation of succinate. TCA cycle metabolism pathway was downregulated to reduce unnecessary energy loss. These self-protection mechanisms can protect cells from hypertonic environments, and help them focus on survival. In addition, we identified 10 hub genes. The findings will aid in the prevention and treatment strategies of S. aureus infections.

Domoic acid (DA) is a potent neurotoxin produced by toxigenic Pseudo-nitzschia blooms and quickly transfers to the benthic anaerobic environment by marine snow particles. DA anaerobic biotransformation is driven by microbial interactions, in which trace amounts of DA can cause physiological stress in marine microorganisms. However, the underlying response mechanisms of microbial community to DA stress remain unclear. In this study, we utilized an anaerobic marine DA-degrading consortium GLY (using glycine as co-substrate) to systematically investigate the global response mechanisms of microbial community during DA anaerobic biotransformation.16S rRNA gene sequencing and metatranscriptomic analyses were applied to measure microbial community structure, function and metabolic responses. Results showed that DA stress markedly changed the composition of main species, with increased levels of Firmicutes and decreased levels of Proteobacteria, Cyanobacteria, Bacteroidetes and Actinobacteria. Several genera of tolerated bacteria (Bacillus and Solibacillus) were increased, while, Stenotrophomonas, Sphingomonas and Acinetobacter were decreased. Metatranscriptomic analyses indicated that DA stimulated the expression of quorum sensing, extracellular polymeric substance (EPS) production, sporulation, membrane transporters, bacterial chemotaxis, flagellar assembly and ribosome protection in community, promoting bacterial adaptation ability under DA stress. Moreover, amino acid metabolism, carbohydrate metabolism and lipid metabolism were modulated during DA anaerobic biotransformation to reduce metabolic burden, increase metabolic demands for EPS production and DA degradation. This study provides the new insights into response of microbial community to DA stress and its potential impact on benthic microorganisms in marine environments.

It has been 14 years since the world's largest Ulva bloom appeared in the Yellow Sea, China in 2007. Although it is clear that the Ulva bloom originates from the culture system of Porphyra yezoensis (Nori) in the southern Yellow Sea, how to control it is still little understood. Since overwintering banks played a crucial role in the development of spring population of green algae on the cultivation ropes, here, a promising method was presented to prevent the development of Ulva bloom by the inactivation of the overwintering banks of green algae on the P. yezoensis cultivation ropes during February and early March. Chlorine dioxide, an environment-friendly disinfectant was used as algaecide with dosage of no lower than 40 mg/L at the contact time of 1 min. The overwintering green algae gradually disappeared within two weeks after the treatment. Furthermore, the growth of spring population of green algae on the cultivation ropes was effectively inhibited for at least eight weeks, which contribute to prevent the formation of floating populations during cultivation facilities collection. It was expected that the present method, if to be applied in the P. yezoensis cultivation areas in southern Yellow Sea, may mitigate the magnitude of the Ulva blooms in the Yellow Sea at a lower cost.

In order to better analyze the influence of electrical equipment on power grid fluctuations, a detection system is designed for power quality monitoring. The system uses 51 single-chip microcomputer as the control core, combined with IM1281B single-phase mutual inductance energy metering module, to collect real-time voltage RMS, current RMS, power factor, apparent power, active power and other electrical parameters of electrical equipment connected to the grid. The standard Modbus-RTU is used for communication between IM1281B and the single-chip microcomputer, which realizes the real-time acquisition and processing of multiple electrical parameters of the electrical equipment connected to the power grid. The experimental results show that, the single-phase power quality monitor designed based on IM1281B is simple in structure, and relatively complete in collecting electrical parameters, which can meet the needs of power quality analysis.

To determine the potential of the recreational marine environment as a dissemination vector of antibiotic-resistant microorganisms, the dissemination of antibiotic-resistant E. coli strains isolated from an urban coastal beach was studied. Sixty-nine and thirteen E. coli strains were isolated from the seawater and sand, respectively, in Fujiazhuang bathing beach, China. The average Antibacterial Resistance Index (ARI) value detected in the seawater is approximately three times that in beach sand. All the isolates from the sand were grouped into one cluster and only the isolates from the municipal sewage outlet were classified into three antibiogram clusters that were observed in the hetero-sites of the E. coli isolates. The E. coli strains with multiple antibiotic resistance (58% of total) were prevalent in the seawater, whereas the isolates from the sand were not detected with multiple antibiotic resistance. A significant association (p < 0.05) between all phenotypic and relative genotypic resistance profiles was observed in the isolates, except in the quinolones resistance genotype. The presence of a class 1 integron was significantly correlated with the resistance of E. coli to sulfonamides, streptomycin, and levofloxacin (p < 0.01). This study revealed that the municipal sewage discharge may impact the dissemination of antibiotic-resistant strains in the urban coastal beach, and that the class 1 integrons play an important role in mediating the resistance of E. coli to sulfonamide antibiotics.

Dalian Jinshitan beach was chosen to evaluate the impact of a typhoon on the bacterial community structure and water quality of a marine bathing beach. The concentration of enterococci was determined by the cultivation method. The bacterial community structure and abundance were analyzed using the 16S rDNA next-generation sequencing and qPCR methods. Results showed that the abundance of cultivable enterococci both in alongshore and offshore seawater increased, while it decreased in dry, wet and submerged sand. The water quality deteriorated immediately after the typhoon, and nearly recovered one month after the typhoon. The typhoon event also decreased the bacterial abundance and changed the bacterial community of the beach. Sphingomonadaceae and Rhodobacteraceae significantly increased in seawater and decreased in dry sand immediately after the typhoon. Human and other fecal taxa increased in water and sand. One month after the typhoon, the diversity and many dominant bacterial taxa nearly recovered in seawater and wet sand. Our work shows that the typhoon changed the bacterial dynamics, deteriorated the water quality and proved the transportation of bacterial taxa and input of fecal pollution between water and beach sand or land. Apart from the impact of the typhoon, the geographical location was another important factor in the changed bacterial community.

In order to assess the ecological quality status of coastal environments in Europe, the AZTI’s Marine Biotic Index (AMBI) and multivariate-AMBI (M-AMBI) have been developed. However, the applicability and validity of these methods worldwide remains in question, particularly for complex ecosystems such as estuaries. The present study, therefore, is an investigation of the relationship between the M-AMBI and different contamination variables in a eutrophic estuary in three seasons (i.e., spring, summer and autumn). In addition, the reliability of taxonomic sufficiency for simplifying M-AMBI operation was tested. The results showed that genus- and family-level data accurately reproduced the spatial-temporal patterns of species-level community assemblages. The M-AMBI values showed a consistent spatial distribution pattern in all sampling seasons, with a decreasing trend along the increasing distance from the estuary inlet. Furthermore, both genus- and family-level results performed nearly as well as species-level data in detecting the seasonal variations of different contaminants (i.e., nutrients and organic enrichment). The taxonomic sufficiency succeeded in this temperate ecoregion is owing to the high aggregation ratios at different taxonomic levels in all sampling events. In general, these findings suggested that application of taxonomic sufficiency based on the M-AMBI provides a simple and efficient method for evaluating variations of ecological quality in the Liaohe Estuary.

Estuarine ecosystems are important in terms of biodiversity processes because there are intense interactions between the river and sea environments. Phytoplankton and zooplankton have been shown to be ecological indicators of the water quality status in estuary ecosystems. Therefore, a comprehensive evaluation of the effects that multiple pressures have on the phytoplankton and zooplankton communities in estuarine ecosystems is essential. In this study, water samples from 29 stations were collected from the Liaohe Estuary over three different seasons, and biotic factors (i.e., phytoplankton and zooplankton) were obtained and compared. The results showed that there were significant temporal and spatial variations in the phytoplankton and zooplankton communities from the Liaohe Estuary. The correlation analyses showed that water temperature was the most important factor regulating the variation in phytoplankton communities, whereas the main driving force for the zooplankton was nutrient concentrations. Large amounts of nutrients entered the estuary in spring and summer due to intensive human activities in the Liaohe River basin. The inflows by the Liaohe River introduced some phytoplankton and zooplankton into the estuary, such as Coscinodicus asteromphalus, Chaetoceros decipiens, and Schmacheria poplesia. The impacts of Liaohe inflows on the estuary region gradually decreased as the distance from the inlet increased and this change was mediated by marine diffusion. The results from this study will improve knowledge about planktonic communities in estuarine ecosystems and provide a theoretical foundation for estuary environmental management.

The environmental toxicity of tetracycline antibiotics to aquatic organisms has attracted increasing attention. The adverse impacts of tetracycline antibiotics on ciliates should be detailed considering the significant roles of protozoa in the microfood web in the soils and other eco-systems. This study for the first time investigated the toxicity of two typical tetracycline antibiotics, tetracycline (TC) and tetracycline hydrochloride (HTC) on two primary model ciliates, Stentor coeruleus and Stylonychia lemnae. The concentrations for 50% of maximal effect (24h‒EC50) of TC and HTC to Stentor coeruleus were 94.4 mg/L and 8.39 mg/L, respectively. Correspondingly, the 24h‒EC50 values of TC and HTC to Stylonychia lemnae were 40.1 mg/L and 14.0 mg/L, respectively. The TC and HTC inhibited the growth rates, reduced the activities of antioxidant enzymes, and damaged the ultra-structures of the tested ciliate cells, with the latter having larger impacts than the former. Based on the experimental works reported herein, the two model protozoan species were proposed to be the toxicity indicators for tetracycline antibiotics, which could work as supplements with the other existing protocols, such as Brochydanio rerio (zebrafish), Limnodrilus (a worm), Chlorogonium elongatum (a green alga) also studied herein.

In this study, we investigated the bacterial diversity in the surface microlayer (

Yalujiang River is a famous border river between China and North Korea. In this study, 22 sample sites (seawater and sediments) were investigated to determine the concentrations of nutrients (dissolved inorganic nitrogen and soluble reactive phosphorus) and trace elements (Hg, As, Pb, Cu, Cd, Cr, and Zn) during the flood season (August). Generally, the concentration of nutrients were higher in the entrance of the estuary than that in the downstream region and the trophic index ranged from moderate to high production, indicating a potential eutrophication risk. With the exception of Cd, the mean concentrations of most metals attained the first level of seawater quality. Sediment pollution assessment was undertaken using contamination factor (CF) and geoaccumulation index (Igeo). The CF values of the seven trace elements were in the following order: Cd>Hg>Pb>As>Cu>Zn>Cr. Both CF and Igeo values indicated the elevated Cd and Hg concentrations in the region. Cluster analysis indicated that the sources of Cu, Cd, Cr, and Zn were mainly derived from copper mine and coastal industrial effluents, whereas Pb, Hg, and As were mainly from vehicle emissions and oil combustion. This study could provide a basis for the sustainable management of the marine ecosystem in this region.

Ammonia-oxidizing bacteria (AOB) play an important role in nitrification in estuaries. The aim of this study was to examine the spatial abundance, diversity, and activity of AOB in coastal sediments of the Liaohe Estuary using quantitative PCR, high-throughput sequencing of the amoA gene coding the ammonia monooxygenase enzyme active subunit, and sediment slurry incubation experiments. AOB abundance ranged from 8.54 × 104 to 5.85 × 106 copies g−1 of wet sediment weight and exhibited an increasing trend from the Liaohe Estuary to the open coastal zone. Potential nitrification rates (PNRs) ranged from 0.1 to 336.8 nmol N g−1 day−1 along the estuary to the coastal zone. Log AOB abundance and PNRs were significantly positively correlated. AOB richness decreased from the estuary to the coastal zone. High-throughput sequencing analysis indicated that the majority of amoA gene sequences fell within the Nitrosomonas and Nitrosomonas-like clade, and only a few sequences were clustered within the Nitrosospira clade. This finding indicates that the Nitrosomonas-related lineage may be more adaptable to the specific conditions in this estuary than the Nitrosospira lineage. Sites with high nitrification rates were located in the southern open region and were dominated by the Nitrosomonas-like lineage, whereas the Nitrosospira lineage was found primarily in the northern estuary mouth sites with low nitrification rates. Thus, nitrification potentials in Liaohe estuarine sediments in the southern open region were greater than those in the northern estuary mouth, and the Nitrosomonas-related lineage might play a more important role than the Nitrosospira lineage in nitrification in this estuary.

A geographically extensive investigation was carried out to analyze the concentrations of heavy metals, PCBs and OCPs in the sediments and marine organisms collected from the Liaohe Estuary. In order to determine the spatial distribution and potential ecological risk of heavy metals, the surface sediments were collected from 44 sites in the Liaohe Estuary. The results showed that the heavy metal contents in the sediments were observed in the following order: Cr (11.2–84.8 mg/kg) > Cu (1.7–47.9 mg/kg) > Pb (4.3–28.3 mg/kg) > As (1.61–12.77 mg/kg) > Cd (0.06–0.47 mg/kg) > Hg (0.005–0.113 mg/kg). In comparison with the concentrations of heavy metals and POPs in other regions, the concentrations of As, Pb and DDTs in the Liaohe Estuary were generally low, and other pollutant concentrations were inconsistent with those reported in other regions. The contamination factor (CF), the pollution load index (PLI), the geoaccumulation index and the potential ecological risk index were used to analyze the pollution situation, which showed that the heavy metal pollution in Liaohe Estuary is mainly dominated by Cd and Hg. The concentrations of the four heavy metals varied significantly in the three kinds of tested organisms (fish, mollusk and crustacean), indicating the different accumulative abilities of the species. The results obtained in this study provide useful information background information for further ecology investigation and management in this region.

Archaea plays an important role in biogeochemical processes. Using the quantitative polymerase chain reaction (qPCR) and Illumina high-throughput sequencing, eight sediment samples collected in Liaohe Estuary were used to investigate the effects of salinity gradient on the archaeal community structure and ecological functions. The results showed that archaeal abundance ranged from 5.1 × 105 to 1.3 × 106 copies/g. Archaeal community included the classes of Thaumarchaeota (69%), Euryarchaeota (29%), and Crenarchaeota (0.01%), respectively. Methanogens in the genera Methanococcoides, Methanoregula, and Methanosaeta and Marine Group I, Candidatus Nitrososphaera, and Nitrososphaera within the ammonia-oxidizing archaea were abundant in freshwater sediments, whereas Marine Benthic Group B and Marine Benthic Group D were abundant in seawater sediments. The positive correlation was observed in between the abundances of Euryarchaeota and salinities (P < 0.05). Physico-chemical analysis in the sediments showed that the temperature and salinity were impacted on the abundance and distribution of archaea significantly (P < 0.05). In general, these results have broadened our understanding on the changes of the archaeal abundance and community structure in estuarine sediment along the salinity gradient.

In this present investigation, a novel design scheme for composite bolted π-joint is proposed, which is mainly improved in layup design. A set of joints are manufactured by resin transfer moulding (RTM) process based on the design above. A detailed investigation by experimental and numerical analysis is conducted on them to study their mechanical behavior and failure mechanism under bending load. In this work, computational models are developed by ABAQUS/Standard, with 3D progressive damage model to predict multiple damage modes in two components of joint. By validation of experimental results, it is indicated that the numerical analysis captures the failure mechanism and provides reasonable accuracy in predicting ultimate load. It is shown that the shear-out failure of lug bolt holes is the failure mode of joints. Besides that, decreasing the thickness of base panel properly will probably cause additional damage to base panel, though it has no significant effect on ultimate load of joints. Also, the location of lug bolt hole is proved to be one of the factors that will influence the load carrying ability of joints.

Ammonia oxidation is an important part of the global nitrogen cycle. Ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) are important players in the ammoxidation process. In this study, 13 sediment samples from the Liaohe estuary were collected in the wet season. The abundances of 16S rRNA and amoA genes were detected by real-time fluorescence quantitative PCR. The diversity and community structure of AOA and AOB were investigated by constructing clone libraries. The AOA and AOB amoA gene abundances ranged from 3.10 × 106–2.85 × 107 and 6.59 × 105–1.20 × 107 copies/g wet deposit, respectively. At all sites, AOA abundance was greater than AOB (AOA: AOB = 2.2–86.5). The ratio of AOA: archaeal 16S rRNA gene abundances and AOB: bacterial 16S rRNA gene abundances were 4.6 × 10−3–1.5 × 10−2 and 1.5 × 10−6–1.0 × 10−4. Phylogenetic analysis showed that the AOA amoA sequences were mainly Nitrosophaera and Nitrosopumilus, and most of the AOB amoA sequences belong to unclassified bacteria, which mainly were detected in estuarine sediments and wetland soils. AOA and AOB community had an obvious spatial heterogeneity. In addition, canonical correspondence analysis showed that the salinity, ammonia, total phosphorus, total organic carbon, sand, and silt content were the main driven factors of AOA and AOB community structure, in which the sand and silt content had a significant contribution.

The ability of denitrifying microorganisms to respond to different ecological pressures remains unknown, especially in marine sediments rich in various heavy metals. Here, gene abundance and transcriptional abundance of five functional denitrification genes (narG, nirK, nirS, norB, and nosZ) in Bohai Sea sediments were examined, and high-throughput Illumina sequencing was used to analyze the community structure of nirK and nirS denitrifying bacteria. The nirS- and nirK-type denitrifying bacteria were classified into different genera. The heavy metal content in sediments was negatively correlated with transcriptional abundance of denitrifying genes, and RNA: DNA ratio for each gene was highest in central Bohai Sea. These results indicated the distribution of nitrite reductase denitrifying bacterial communities was affected by depth, total nitrogen, total phosphorus and sediment grain size. Heavy metal contamination in sediment environment may negatively regulate the transcriptional abundance of denitrifying genes and cause geographical differences in the denitrifying bacterial community structure.

Many un-developed countries select fecal indicator bacteria (FIB) based on the recommendation of the U.S. EPA, or WHO criteria. To prove its applicability in China, FIB, human markers, and 15 typical bacterial pathogens were assessed using both culture dependent and independent methods (PCR, gene chip, and quantitative PCR) in Xinghai bathing beach of China. In most cases, enterococcus can indicate the pollution phenomenon of the main pathogenic bacteria (Staphylococcus aureus, Aeromonas caviae and Streptococcus faecalis), while only correlated with human Bacteroides and Staphylococcus aureus, which all suggested that the use of enterococci may not accurately assess the risk of most enteric pathogenic bacteria. Therefore, periodic surveying of human specific Bacteroides is strongly recommended, the monitoring of the most prevalent enteric pathogen, Aeromonas caviae, and the autochthonous pathogen, Vibrio parahaemolyticus should also be taken into consideration in the routine monitoring to protect bathers health.

Previous studies that have investigated marine oil pollution have predominantly focused on petroleum hydrocarbons. Naphthenic acids (NAs), in contrast, are toxins that are less well studied. Following the Dalian oil spill accident, monitoring surveys were carried out to investigate NAs in Dalian Bay sediments. Concentrations of NAs were between 14.826 and 34.279 mg kg−1, with acyclic and motorcycle carboxylic acids (43.28% and 35.12%, respectively) being the dominant components. NAs were 10–30 times more abundant than polycyclic aromatic hydrocarbons (PAHs) in the sediment. Further correlation analysis showed the abundance of NAs was highly correlated with total PAH levels (0.705, p

This present work investigated the failure mechanism of a novel composite bolted π-joint subjected to bending load by experimental and finite element simulation. A test sample manufactured by resin transfer moulding process (RTM) was tested. A 3D progressive damage model developed in ABAQUS/Standard was used to simulate the failure of the π-joint. Based on good correlation of failure load and damage distribution between experimental results and FE prediction, further investigation was extended to the effect of two primary assembly clearances on mechanical behavior of the π-joint. The study results reveal that delamination of the fillet region in L-preform is the π-joint's failure mode. Moreover, the assembly clearances have little effect on the failure load of the joint.

The horizontal distribution and temporal variation of bacterial indicators (total coliforms (TC), fecal coliforms (FC), enterococcus (EC) and Escherichia coli (E. coli)) were investigated to identify the proper bacterial indicators for a marine bathing beach in China. Two different sampling efforts were conducted during dry weather and two large rain events at Xinghai Bathing Beach in Dalian, China. Samples were collected from three different water depths and analyzed for the four indicator bacteria. The results indicated that all four bacterial indicators exceeded the single sample standards at different levels. Specifically, the water quality exceeded the standard for TC, FC, EC and E. coli in 7%, 28%, 38% and 10% of the samples, respectively. Comparison of the rate of the indicators before and after rainfall revealed a significant increasing post-rainfall. The concentrations of bacteria differed significantly with distance from the shoreline, with knee-depth near the shore exceeding the standard most frequently. This was primarily due to contamination by excessive sewage discharge and rainfall. Based upon the concentration of indicators and exceedance rates, as well as the correlation between indicators, both EC and FC should be evaluated at the same time as fecal pollution bacterial indicators in marine bathing beaches in China.

Short-chain chlorinated paraffins (SCCPs) are known to disturb thyroid hormone (TH) homeostasis in rodents. However, the mechanism remains to be fully characterized. In this study, male Sprague Dawley rats received SCCPs (0, 1, 10, or 100mg/kg/day) via gavage once a day for consecutive 28days. Plasma and hepatic TH concentrations, thyrocyte structure, as well as thyroid and hepatic mRNA and protein levels of genes associated with TH homeostasis were examined. Moreover, we performed molecular docking to predict interactions between constitutive androstane receptor (CAR), a key regulator in xenobiotic-induced TH metabolism, with different SCCP molecules. Exposure to SCCPs significantly decreased the circulating free thyroxine (T4) and triiodothyronine (T3) levels, but increased thyroid-stimulating hormone (TSH) levels by a feedback mechanism. Decreased hepatic T4 and increased hepatic T3 levels were also seen after 100mg/kg/day SCCPs exposure. SCCPs didn't show any significant effects on the expression of thyroid TH synthesis genes or thyrocyte structure. However, stimulation effects were observed for mRNA and protein levels of hepatic uridine diphosphoglucuronosyl transferase (UGT) 1A1 and organic anion transporter 2, suggesting an accelerated TH metabolism in rat liver. The increased cytochrome P450 2B1 but not 1A1 mRNA and protein levels indicated that the CAR signaling was activated by SCCPs exposure. According to docking analysis, SCCPs form hydrophobic interactions with CAR and the binding affinity shows dependency on chlorine content. Overall, our data showed that CAR implicated enhancement of hepatic TH influx and degradation could be the main cause for SCCPs induced TH deficiency in male rats.

To examine the bacterial community structure in the Fildes Peninsula, King George Island, Antarctica, we examined the bacterial diversity and community composition of samples collected from lacustrine sediment, marine sediment, penguin ornithogenic sediments, and soils using culture-dependent and culture-independent methods. The 70 strains fell into five groups: Actinobacteria, Bacteroidetes, Firmicutes, Gammaproteobacteria, and Betaproteobacteria. Bacterial diversity at the phylum level detected in Denaturing Gradient Gel Electrophoresis (DGGE) profiles comprised Proteobacteria (including the subphyla Alpha-, Beta-, Gamma-, Deltaproteobacteria), Bacteroidetes, Firmicutes, Chlorobi, and Deinococcus-Thermus. Gammaproteobacteria was identified to be the dominant bacterial subphylum by cultivation and DGGE method. By cluster analysis, the overall structure and composition of bacterial communities in the soil and lacustrine sediment were similar to one another but significantly different from bacterial communities in penguin ornithogenic sediment and marine sediment, which were similar to one another. The majority of 16S rDNA sequences from cultured bacteria were closely related to sequences found in cold environments. In contrast, a minority of 16S rDNA sequences from the DGGE approach were closely related to sequences found in cold environments.

Levels, sources, and potential ecological risks of polycyclic aromatic hydrocarbons (PAHs) in surface seawater and sediments from the northern Liaodong Bay of China were seasonally investigated. Total concentrations of 16 PAHs varied from 145.96 ng/L to 896.58 ng/L in seawater, and from 191.99 ng/g to 624.44 ng/g in sediments. PAH concentrations in seawater differed significantly, whereas those in sediments exhibited a relatively stable pattern across seasons. PAHs with low molecular weight were predominant in seawater, but PAHs with high molecular weight were abundant in sediments. Crop straw and coal combustion were the main PAH pollution sources. The current levels of PAHs in the northern Liaodong Bay are relatively moderate compared with those in other bays and estuaries. Sediment from all sampling sites is characterized by low to medium ecotoxicological risk. No highly negative toxic effect could occur on the organisms and ecosystems in the northern Liaodong Bay.

The concentrations, compositional profiles, possible sources of polybrominated diphenyl ethers (PBDEs) in sediments of the Daliao River Estuary as well as the factors influencing the distribution of PBDEs were investigated. The total concentrations of PBDEs ranged from 0.13 to 1.98 ng g(-1)d.w. BDE209 was the dominating congener in all sediment samples, indicating the pollution of PBDEs in the Daliao River Estuary mainly came from the use of deca-BDE commercial mixtures. The intrusion of sea waters promoted the deposition of the colloid-associated PBDEs in the estuary. There were significantly negative correlations between PBDE concentration in sediment with pH value and salinity in the bottom water. The higher river flow in the flood season (summer) obviously accelerated the transport of PBDEs, and thereby increased the risk of PBDE contamination to the deep ocean. Moreover, a positive correlation between TOC and PBDE distributions was observed, suggesting that TOC regulated the distributions of PBDEs in sediments of Daliao River Estuary.

The objective of this study is to understand the contamination of human enteric viruses in economic shellfish along the Chinese coast, an important issue of ensuring the seafood safety.We established the specific, sensitive and high-throughput gene chip technology, to investigate the contamination of economic shellfish by enteric viruses across a large geographical region of China.The percentage of positive samples for each virus was as follows: Hepatitis A Virus 4.3%, norovirus 14.8%, rotavirus 6.2%, astrovirus 5.6%, and adenovirus 9.9%. In these five viruses, norovirus was contaminated in the first place. The results detected by gene chip were highly consistent with that of polymerase chain reaction (PCR). The economic shellfishes in shellfish-growing areas along the coastal cities were all contaminated with enteric viruses at different levels. However, there was no significant correlation between any two cities. In the selected 6 economic shellfishes, oyster had the highest positive rate of enteric viruses, followed by blood clam.The contamination of shellfish with human enteric viruses was common across the main coastal cities of China, indicating a potential public health threat from seafood.

Limited by sampling frequency and detection methods, current recreational water monitoring programs often fail to protect public health, especially after heavy rain or flooding, when microbial water quality can change rapidly. In order to assess the variations in the microbial indicators and to develop a scientific warning system, we conducted an intensive sampling project at the No. 1 Bathing Beach. The results show that, during dry weather, the detection rate of Enterococcus was significantly lower than that of Faecal coliform bacteria. On these days, water quality was mainly impacted by pollutants brought in by swimmers than by stormwater outfall. During wet weather, rainfall and microbial bacterial concentrations showed a positive correlation. Trends in the two microbial bacteria were approximately the same. With increasing distance from the shore, the detection rate of microbial bacteria gradually decreased. Microbial bacteria concentrations increased markedly during high tide and under a south wind.

Myostatin (MSTN) is a member of the transforming growth factor-β superfamily which could play an important role in negatively regulating skeletal muscle growth and development in mammal and non-mammal species. In the present study, a MSTN1 gene (designated as VvMSTN1) was cloned and characterized in one flatfish species, spotted halibut (Verasper variegatus). In the 3078 bp genomic sequence, three exons, two introns and a promoter sequence were identified. Sequence analysis of the promoter region revealed that it contained several cis-regulatory elements such as CAAT-box, TATA-box and E-boxes. The deduced protein sequence included a signal peptide, a TGF-β propeptide in the N-terminal region and the TGF-β active peptide in the C-terminal region. Phylogenetic analysis suggested that VvMSTN1 is an orthologue of teleost MSTN1 proteins which arose along with MSTN2 during a duplication event at the base of teleost evolution. Quantitative real-time PCR analysis revealed that VvMSTN1 mRNA was ubiquitously expressed in all nine tested tissues, with the most transcriptionally abundant in skeletal muscle. A primary assessment of sequence variability revealed five single nucleotide polymorphisms (SNPs) existed in the promoter region, among which three (G-653T, T-355C and G-253A) were genotyped with an advanced melting temperature (T(m))-shift method and tested for their association with growth traits (body length, body depth and total mass). Results indicated that genotype CC of locus T-355C had significantly higher growth traits than genotype TC and TT (P0.05) in female spotted halibut. These results suggest that V. variegatus MSTN could be selected as a candidate gene for the future molecular breeding of stains with enhanced individual growth performance.

The working properties is detail anglicized and studied on linear motion guides (LMD), in different curvature ratio of ball diameter and radius of ring of guide rail and slider of LMG in the paper. LMG's mechanics model is built. ABAQUS soft is applied to numerical modeling and calculating. The rigidity curves of LMG are gained in different of curvature ratio and loads. The study has some reference value for design of structure and parameters.

The concentrations, compositional profiles, and potential ecological risk of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs) and polychlorinated naphthalenes (PCNs) in sediments of the Daliao River Estuary were investigated. Total concentrations of PCDD/Fs, PCBs, and PCNs were in the range of 11.3-133.2 ng/kg dry weight (dw), 1 971-37 632 ng/kg dw and 33.1-284.4 ng/kg dw, respectively. The total TEQ values varied from 0.37 to 4.08 ng/kg dw, with the dominant contributions by PCDD/Fs, then by PCBs and PCNs. The spatial distributions of PCDD/Fs, PCBs and PCNs in the river estuary were much related to hydrodynamic conditions. The risk of contamination to the deeper sea was increased in the flood seasons. Moreover, our data confirmed that both organic matter in sediments and molecular properties of dioxin-like compounds were the factors which strongly influenced the partition behavior of these dioxin-like compounds between sediments and water phase in the estuarine zone. (C) 2011 Elsevier Ltd. All rights reserved.

The principle of solid abrasives lapping is that the abrasives are fixed and made into a special lapping tool; the workpiece is lapped in high speed lapping machine tool. It possesses many advantages compared with traditional low speed lapping with particulate abrasives, e.g. high machining efficiency, low machining cost, high and stable machining accuracy. So the highly efficient lapping method has been paid close attention to. This paper made a study on surface micro topography of different material by solid abrasive lapped at high speed. In experiments the lapping technique parameter is fixed, and different workpiece which are made by T10 steel, carbide, ceramic glass and alumina ceramics are lapped. The surface micro topography is measured by SEM, from the measuring result, it can be known that there is some shallow scribe on the surface of T10 steel, and the obvious plastic deformation can be observed. The SEM pictures show that there is some scribe on the surface of ceramics glass after lapped, with more magnification times many micro cracking and some plastic hump can be observed on the scribe. These scribes and humps are first cause of depressing surface quality, and these micro cracking can result in a lot of diffuse reflection on workpiece surface, it decreases the glossiness of mirror surface. On the surface of alumina ceramics there are a lot of defects, the size of such defect is more than the scribe of abrasive, it can be sure that the defect is not produced by lapping, so the material quality is an important effect fact to surface macro topography. On the surface of carbide there are a little of scribe and air cavity, and the scribe is very shallow; the defect of powder metallurgy martial is the primary reason.