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Arginine rich, mutated in early stage of tumours (Armet), is a well-characterized bifunctional protein as an unfolded protein response component intracellularly and a neurotrophic factor extracellularly in mammals. Recently, a new role of Armet as an effector protein mediating insect-plant interactions has been reported; however, its molecular mechanisms underlying the regulation of plant defences remain unclear. We investigated the molecular mechanisms underlying whitefly-secreted Armet-mediated regulation of insect-plant interaction by agrobacterium-mediated transient expression, RNA interference, electrical penetration graph, protein-protein interaction studies, virus-induced gene silencing assay, phytohormone analysis and whitefly bioassays. Armet, secreted by Bemisia tabaci whitefly, is highly expressed in the primary salivary gland and is delivered into tobacco plants during feeding. Overexpression of the BtArmet gene in tobacco enhanced whitefly performance, while silencing the BtArmet gene in whitefly interrupted whitefly feeding and suppressed whitefly performance on tobacco plants. BtArmet was shown to interact with NtCYS6, a cystatin protein essential for tobacco anti-whitefly resistance, and counteract the negative effects of NtCYS6 on whitefly. These results indicate that BtArmet is a salivary effector and acts to promote whitefly performance on tobacco plants through binding to the tobacco cystatin NtCYS6. Our findings provide novel insight into whitefly-plant interactions.

Trichogramma wasps are commonly used as biocontrol agents to manage lepidopteran rice pests in rice fields. However, lepidopteran pests synergistically occur with rice planthoppers which are not targeted by Trichogramma. The use of Trichogramma parasitoids in field-based pest control efforts is greatly affected by the application of insecticides targeting planthoppers. As such, insecticide-resistant strains of Trichogramma are urgently needed for the incorporation of these beneficial natural enemies into integrated pest management programs in rice agroecosystems. In the present study, Trichogramma japonicum Ahmead (Hymenoptera: Trichogrammitidae) and Trichogramma chilonis Ishii (Hymenoptera: Trichogrammitidae) were treated with sublethal doses of four insecticides which target rice planthoppers, to generate tolerant strains in the laboratory. The resistance rate of T. japonicum to imidacloprid was the highest (17.8-folds) after 10 successive treatments and experienced 2.5, 4.72, and 7.41-fold increases in tolerance to thiamethoxam, buprofezin, and nitenpyram, respectively. Tolerance of T. chilonis to imidacloprid, thiamethoxam, buprofezin, and nitenpyram were 8.8, 6.9, 4.43, and 5.67-fold greater, respectively. The emergence and deformity (without spreading wings or short wings) rates of T. japonicum and T. chilonis gradually recovered with an increased exposure time of treatments. The fecundity of T. japonicum treated with thiamethoxam was significantly higher than that of the control and T. chilonis treated with thiamethoxam and nitenpyra. Our results demonstrate that screening for insecticide-tolerant/resistant Trichogramma strains was feasible, especially in the pairing of T. japonicum and imidacloprid, which could provide a valuable biological control tool that can be combined with traditional chemical control strategies for use in IPM of rice agroecosystems.

Nicotiana benthamiana acylsugar acyltransferase (ASAT) is required for protection against desiccation and insect herbivory. Knockout mutations provide a new resource for investigation of plant-aphid and plant-whitefly interactions. Nicotiana benthamiana is used extensively as a transient expression platform for functional analysis of genes from other species. Acylsugars, which are produced in the trichomes, are a hypothesized cause of the relatively high insect resistance that is observed in N. benthamiana. We characterized the N. benthamiana acylsugar profile, bioinformatically identified two acylsugar acyltransferase genes, ASAT1 and ASAT2, and used CRISPR/Cas9 mutagenesis to produce acylsugar-deficient plants for investigation of insect resistance and foliar water loss. Whereas asat1 mutations reduced accumulation, asat2 mutations caused almost complete depletion of foliar acylsucroses. Three hemipteran and three lepidopteran herbivores survived, gained weight, and/or reproduced significantly better on asat2 mutants than on wildtype N. benthamiana. Both asat1 and asat2 mutations reduced the water content and increased leaf temperature. Our results demonstrate the specific function of two ASAT proteins in N. benthamiana acylsugar biosynthesis, insect resistance, and desiccation tolerance. The improved growth of aphids and whiteflies on asat2 mutants will facilitate the use of N. benthamiana as a transient expression platform for the functional analysis of insect effectors and resistance genes from other plant species. Similarly, the absence of acylsugars in asat2 mutants will enable analysis of acylsugar biosynthesis genes from other Solanaceae by transient expression.

Midgut juice plays an important role in food digestion and detoxification in insects. In order to understand the potential of midgut juice of Cnaphalocrocis medinalis (Guenee) to degrade Bt proteins, the enzymatic activity of midgut juice and its degradation of Bt proteins (Cry2A, Cry1C, Cry1Aa, and Cry1Ac) were evaluated in this study through protease inhibitor treatments. The activities of total protease in midgut juices were significantly inhibited by phenylmethylsulfonyl fluoride (PMSF), tosyl-L-lysine chloromethyl ketone (TLCK), pepstatin A and leupeptin. The enzymatic activity of chymotrypsin was significantly inhibited by PMSF, and enzymatic activity of trypsin was significantly inhibited by ethylenediaminetetraacetic acid (EDTA), PMSF, tosyl phenylalanine chloromethyl ketone (TPCK), TLCK and trans-epoxysuccinyl-L-leucylamido-(4-guanidino) butane (E-64). EDTA could significantly inhibit the degradation of Cry2A by C. medinalis. EDTA, PMSF, TPCK, and TLCK could inhibit the degradation of Cry1C and Cry1Aa. EDTA, PMSF, TPCK, TLCK, and E-64 could inhibit the degradation of Cry1Ac. Our results indicated that some protease inhibitors hindered various enzymatic activities in the larval midgut of C. medinalis, which may reduce the insect's ability to degrade Bt toxins. These findings may aid the application of protease inhibitors in the management of this insect pest in the future.

Midgut extracts play crucial roles in food digestion and detoxification. We evaluated the effect of pH on the profiles of the midgut extracts in rice leaffolder, Cnaphalocrocis medinalis and the degradation of activated Bt-toxins by the midgut extracts under different pH conditions. Total protease activity increased slightly with the increase with the simulated pH in the midgut extracts and the maximal protease activity was observed at pH 10.5, while an upward trend was observed as the pH of reaction buffer increased. Activity of chymotrypsin-like enzymes increased with pH, both in the buffer and midgut extracts, while the activity of trypsin-like enzyme was unaffected. Degradation of the activated Cry2A by the midgut extracts enhanced as the pH increased. Cry2A was fully degraded into smaller segments at pH 9.0–10.5. Activated Cry1C protein at pH 9.0–10.5 was partially degraded by the midgut extracts. Activated Cry1Aa and Cry1Ac were partially degraded into fragments by the midgut extracts at high pH. These results will facilitate our further understanding of the interactions between C. medinalis and the Cry toxin.

Phloem-feeding insects feed on plant phloem using their stylets. While ingesting phloem sap, these insects secrete saliva to circumvent plant defenses. Previous studies have shown that, to facilitate their feeding, many phloem-feeding insects can elicit the salicylic acid- (SA-) signaling pathway and thus suppress effective jasmonic acid defenses. However, the molecular basis for the regulation of the plant's defense by phloem-feeding insects remains largely unknown. Here, we show that Bt56, a whitefly-secreted low molecular weight salivary protein, is highly expressed in the whitefly primary salivary gland and is delivered into host plants during feeding. Overexpression of the Bt56 gene in planta promotes susceptibility of tobacco to the whitefly and elicits the SA-signaling pathway. In contrast, silencing the whitefly Bt56 gene significantly decreases whitefly performance on host plants and interrupts whitefly phloem feeding with whiteflies losing the ability to activate the SA pathway. Protein-protein interaction assays show that the Bt56 protein directly interacts with a tobacco KNOTTED 1-like homeobox transcription factor that decreases whitefly performance and suppresses whitefly-induced SA accumulation. The Bt56 orthologous genes are highly conserved but differentially expressed in different species of whiteflies. In conclusion, Bt56 is a key salivary effector that promotes whitefly performance by eliciting salicylic acid-signaling pathway.

The event-based quantitative trading system can avoid human subjective judgment errors in the stock and futures trading markets, and the development of quantitative trading strategies based on "high probability" events in history can obtain ideal returns. It is essentially a discrete event processing system. It uses a computer to simulate and process random events with high probability. The core of the quantitative trading system is its engine part driven by transaction data. These transaction data can be regarded as a series of discrete events. This article summarizes and introduces the strategy-driven engine part of the quantitative trading system based on the open source quantitative trading framework VNPY as an example. It mainly includes a real trading operation engine module and a strategy backtesting module. The real trading engine links the trading market to obtain real-time data and uses quantitative strategies for trading; the backtest module runs to test trading strategies and optimizes the strategy parameters.

Nicotiana benthamianais used extensively as a platform for transient gene expression and as a model system for studying plant-virus interactions. However, many tobacco-feeding generalist herbivores, includingMyzus persicae(green peach aphid),Bemisia tabaci(whitefly),Macrosiphum euphorbiae(potato aphid),Heliothis virescens(tobacco budworm),Trichoplusia ni(cabbage looper), andHelicoverpa zea(corn earworm), grow poorly onN. benthamiana, limiting its utility for research on plant-insect interactions. Using CRISPR/Cas9, we generated knockout mutations in twoN. benthamianaacylsugar acyltransferases,ASAT1andASAT2, which contribute to the biosynthesis of insect-deterrent acylsucroses. Whereasasat1mutations reduced the abundance of two predominant acylsucroses,asat2mutations caused almost complete depletion of foliar acylsucroses. The tested hemipteran and lepidopteran species survived, gained weight, and/or reproduced significantly better onasat2mutant plants than on wildtypeN. benthamiana. Furthermore, bothasat1andasat2mutations reduced the water content and increased the temperature of leaves, indicating that foliar acylsucroses can protect against desiccation. Two experiments demonstrated the utility of theN. benthamiana asat2mutant line for insect bioassays. Transmission of turnip mosaic virus byM. persicaewas significantly improved by anasat2mutation. Tobacco rattle virus constructs were used for virus-induced gene silencing ofacetylcholinesterase,squalene synthase,toll-like receptor 7, andtubulin-specific chaperon Dgenes inB. tabaci, an experiment that would have been difficult with wild-typeN. benthamianadue to high insect mortality. Additionally, the absence of acylsugars inasat2mutant lines will simplify transient expression assays for the functional analysis of acylsugar biosynthesis genes from other Solanaceae.

Aiming at the difficulties in hydraulic fracturing of tight and thin interbedded reservoirs, dynamic multi-stage temporary plugging fracturing was proposed. This technology is a kind of multi-layer fracturing, during which, natural selective near-wellbore plugging is realized by temporary plugging materials, to improve the interlaminar fracturing effectiveness of longitudinal reservoir. A novel coated temporary plugging agent BFD-1 was developed, whose dissolution time and temperature can be controlled by the introduction of functional monomer SM. Temporary plugging pressure of BFD-1 is more than 50 MPa in lab, and it can effectively propped the fractures after degradation by special processing technology. Evaluation device for plugging ability of temporary plugging agent by dynamic injection and simulating apparatus of near-wellbore temporary plugging were independently developed, key process parameters optimization technology of dynamic multi-stage temporary plugging fracturing were formed, and the design methods were established. Field tests were carried out in 2 wells in Changqing oilfield, after temporary plugging, fracturing pressure rised rapidly, then declined sharply, with obvious indication of formation fracture pressure. In addition, subsequent construction pressure and instantaneous shut-in pressure both increased significantly, which has the indication of new fracture fracturing. Daily production for oil test of the 2 wells both exceeded 41 tons, which showed that this technology successfully achieved significant stimulation effect.

The dried root of Salvia miltiorrhiza is a renowned traditional Chinese medicine that was used for over 1000 years in China. Salvianolic acid B (SalB) is the main natural bioactive product of S. miltiorrhiza. Although many publications described the regulation mechanism of SalB biosynthesis, few reports simultaneously focused on S. miltiorrhiza root development. For this study, an R2R3-MYB transcription factor gene (SmMYB52) was overexpressed and silenced, respectively, in S. miltiorrhiza sterile seedlings. We found that SmMYB52 significantly inhibited root growth and indole-3-acetic acid (IAA) accumulation, whereas it activated phenolic acid biosynthesis and the jasmonate acid (JA) signaling pathway. Quantitative real-time polymerase chain reaction (qRT-PCR) analyses revealed that SmMYB52 suppressed the transcription levels of key enzyme-encoding genes involved in the IAA biosynthetic pathway and activated key enzyme-encoding genes involved in the JA and phenolic acid biosynthesis pathways. In addition, yeast one-hybrid (Y1H) and dual-luciferase assay showed that SmMYB52 directly binds to and activates the promoters of several key enzyme genes for SalB biosynthesis, including SmTAT1, Sm4CL9, SmC4H1, and SmHPPR1, to promote the accumulation of SalB. This is the first report of a regulator that simultaneously affects root growth and the production of phenolic acids in S. miltiorrhiza.

Hepatitis B virus (HBV) infection is a major global health problem and causes liver damage as cirrhosis of the liver or liver cancer. Development of an accurate, sensitive and reproducible detection method for detecting and monitoring HBV DNA is very necessary and urgent.The aims were to evaluate the analytical performances of the fully automated Pre-NAT system comparing to domestic assay, and to explore the role of highly sensitive quantification of HBV DNA in the management of chronic HBV infection.Pseudo-viral particles at high HBV DNA concentration were serially diluted to assess linear range. Accuracy and lower limit of detection were assessed by determining a panel of HBV standard substance. HBV DNA positive clinical specimen and internal quality control were measured 20 times to evaluate precision and reproducibility. 20 non HBV-infected specimens were used for the specificity assay. 96 chronic hepatitis B samples were quantified for HBV DNA to evaluating the correlation between the new test and Da-an assay. HBV serological markers were detected using ELISA method.Pre-NAT quantitated HBV DNA levels covered a wide dynamic range (10 logs) with a close correlation between expected and observed values (r=0.999, P0.05), satisfactory precision and higher specificity. The lower detection limit was 20IU/mL. Comparability assay showed Pre-NAT had a good agreement with but more sensitive than Da-an assay (t=0.149, P0.05). HBV DNA level was partially correlated to but more reliable and sensitive than serological evidence in reflecting the viral level.This novel fully-automated real-time PCR assay exhibits good analytical and clinical performances for highly sensitive detection of HBV DNA. It is well suited for monitoring antiviral responses and making treatment strategies according to current clinical practice guidelines for the management of chronic HBV infection.

Human papillomavirus infection is a major health problem and caused substantial benign and malignancy diseases among female and male worldwide. We aim to investigate the epidemiology of high-risk human papillomavirus (HR-HPV) and related diseases in Suzhou population. As well as evaluating the potential benefit of a nine-valent HPV vaccine (regardless of HPV-6 and -11) in Suzhou. A total of 40,108 people aged 13-89 years were retrospectively examined by database retrieval from 2010 to 2015. Thirteen genotypes (16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, and 66) of HR-HPV were detected using Tellgenplex™ xMAP™ HPV DNA Test assay. The overall prevalence of HR-HPV was 21.1%, the female and male account for 96.4% and 3.6%, respectively. The infection rate among male (25.6%, 367/1,432) was significantly higher than that among female (20.9%, 8,100/38,676), X2 = 17.341 (P

In order to clarify the feasibility of the banker plant system "Leesia sayanuka-Nlilaparvata muiri-Tytthus chinensis" to control rice planthooper, the effects of the combination of rice, L. sa-yanuka, N. lugen and N. muiri on the adult morphology, population growth, oviposition and feeding selectivity of T. chinensis were carried out in the present study. The results showed that the body size of male and female adults of T. chinensis rice population (feeding on N. lugens eggs) were significantly larger than those of T. chinensis population (feeding on N. muiri eggs). Population growth parameters including fecundity, net productive rate, innate capacity for increase, finite rate of increase of L. sayanuka feeding on N. lugens eggs were significantly higher than those of L. sayanuka feeding on N. muiri eggs. However, the population growth ability of L. sayanuka feeding on N. muiri was still high enough to expand the population. For the oviposition selection, both rice population and L. sayanuka population preferred laying eggs on rice than on L. sayanuka. Meanwhile, there was no significant difference in the predation of females, males and nymphs to N. lugens eggs or N. muiri eggs between rice population and L. sayanuka population. At last, based on our results, we discussed the feasibility of establishing the banker plant system "L. sayanuka-N. muiri-T. chinensis" in rice fields.为明确用于防治稻飞虱的“秕谷草-伪褐飞虱-中华淡翅盲蝽”载体植物系统的可行性,本文开展了靶标作物水稻、载体植物秕谷草和靶标害虫褐飞虱、替代猎物伪褐飞虱组合对中华淡翅盲蝽成虫形态、种群增长参数、产卵选择性和取食选择性的影响研究.结果表明: 中华淡翅盲蝽水稻种群(取食褐飞虱卵)的雌雄成虫个体均显著大于秕谷草种群(取食伪褐飞虱卵).取食褐飞虱卵的中华淡翅盲蝽种群增长参数单雌产卵量、净增长率、内禀增长率、周限增长率明显高于取食伪褐飞虱卵的种群,但取食伪褐飞虱卵也有较高的种群增长能力,足以扩繁种群.对于靶标作物水稻和载体植物秕谷草,无论是水稻种群还是秕谷草种群均偏好在水稻上产卵.同时,2个种群的雌虫、雄虫和若虫对褐飞虱卵和伪褐飞虱卵捕食量没有显著性差异.在上述研究基础上,讨论了在田间建立“秕谷草-伪褐飞虱-中华淡翅盲蝽”载体植物系统的可行性.

Using methyl triethoxysilane, tetrabutyl titanate and ethyl acetoacetate as raw materials, the Si-Ti polymer was synthesized to prepare Si-Ti polymer/montmorillonite nanocomposites. The effects of OMMT content on the impact properties and barrier performance of nanocomposites were investigated. The results show that with the increasing of OMMT content, the impact properties of nanocomposites are improved significantly. The impact strength of nanocomposite with 10wt% OMMT is about twice times than that without OMMT. The gas barrier properties of nanocomposites are also improved significantly. Compared with pure Si-Ti polymer, the water absorption of nanocomposite with 6wt% OMMT is decreased by 60.3%.

The polytetrafluoroethylene (PTFE) matrix composites reinforced by polyphenylene sulfide (PPS) fiber and poly-p-phenelenferephthalamide (PPTA) fiber were prepared by the processes of mechanical blending, compression molding and sintering. The fractured surfaces of impacting specimens were examined by scanning electron microscopy (SEM). The tribological properties of the composites were investigated on M-2000 wear tester at dry friction condition. The wear mechanism was also discussed and the wear surfaces were examined by SEM. The result indicates that fibers which diffused in PTFE matrix wind with PTFE molecule chain, and then form grid structure. The load-bearing capacity of composites can be obviously enhanced and the trend of block fragmentation’s slide is inhibited, so that the tribological properties are improved markedly. The friction coefficient of composites is reduced by adding graphite which also prevents fibers leaving. The tribological properties of PTFE matrix composites is greatly improved because of the synergistic effect between fibers and graphite, which has good prospect for low loading application.

BACKGROUND Tomato yellow leaf curl virus (TYLCV), a member of the genus Begomovirus within the family Geminiviridae, is an important pathogen of tomato in many tropical, subtropical and temperate regions. TYLCV is exclusively transmitted by the whitefly Bemisia tabaci in a circulative manner. The viral coat protein (CP) has been assumed to play important roles in the entry of TYLCV into the insect midgut cells. RESULTS Testing the hypothesis that CP plays an important role in TYLCV acquisition by B. tabaci, a soluble form of the CP was expressed and purified. The purified recombinant CP made it possible to examine the function of TYLCV CP without other viral proteins. In an in vivo binding assay, specific binding of TYLCV CP to B. tabaci midguts was detected when purified CP was fed to B. tabaci. In addition, real-time polymerase chain reaction analysis of virus titre revealed that B. tabaci fed with purified CP had reduced the level of virus in their midgut compared with those fed with bovine serum albumin or maltose-binding protein. These results suggest that binding of TYLCV CP to the B. tabaci midgut specifically inhibits virus acquisition. CONCLUSIONS The findings that TYLCV CP binds to B. tabaci midguts and decreases virus acquisition provide direct evidence that CP mediates the attachment of TYLCV to receptors on the epithelial cells of the B. tabaci midgut. © 2014 Society of Chemical Industry

Superoxide dismutases (SODs) are a group of important antioxidant defense enzymes. In this study, a putative extracellular Cu/Zn superoxide dismutase (ecCuZnSOD) complementary DNA was cloned and characterized from the whitefly, Bemisia tabaci. Quantitative polymerase chain reaction analysis showed that the expression level of Bt-ecCuZnSOD was more than 10-fold higher in the invasive Middle East Asia Minor 1 (MEAM1) than in the native Asia II 3 species of the B. tabaci species complex. After exposure to low temperature (4 °C), the expression of Bt-ecCuZnSOD gene was significantly up-regulated in MEAM1 but not in Asia II 3. Furthermore, the expression level of B. tabaci intracellular CuZnSOD (Bt-icCuZnSOD), Bt-ecCuZnSOD and mitochondrial MnSOD (Bt-mMnSOD) was compared after transferring MEAM1 and Asia II 3 whiteflies from favorable (cotton) to unfavorable host plants (tobacco). On cotton, both CuZnSOD genes were expressed at a higher level in MEAM1 compared with Asia II 3. Interestingly, after transferring onto tobacco, the expression of Bt-ecCuZnSOD was significantly induced in Asia II 3 but not in MEAM1. On the other hand, while Bt-mMnSOD was expressed equally in both species on cotton, Bt-mMnSOD messenger RNA was up-regulated in MEAM1 on tobacco. Consistently, enzymatic activity assays of CuZnSOD and MnSOD demonstrated that CuZnSOD might play an important protective role against oxidative stress in Asia II 3, whereas MnSOD activation was critical for MEAM1 whiteflies during host adaptation. Taken together, our results suggest that the successful invasion of MEAM1 is correlated with its constitutive high activity of CuZnSOD and inducible expression of MnSOD under stress conditions.

China has the highest greenhouse-based production in the world. In 2010, the area of greenhouses devoted to vegetable production was estimated at 4.7 million ha. With the increasing costs of pest control, expanding pesticide resistance and the growing consumer concern regarding pesticide residues in fresh vegetables, a strong demand for applying non-chemical control methods is emerging in China. Biological control in the greenhouse environment is a viable alternative to pesticide use from both environmental and economic perspectives. Although we have only 17 cases of fully documented, successful biological control operations from China, involving 8 crops, 8 pest species and 14 species of natural enemies, the use of the biological control agents is much more widespread. There are 7 commercial companies and facilities producing 21 species of natural enemies, and most of them are available country-wide. Several of these employ a rearing system using artificial diets, and many now move to an integrated production system, including the mass production of the biocontrol agents, quality control, methods of long-distance transportation, release recommendations, and user feedback. While initially these systems relied on introduced natural enemies, they increasingly develop modified systems using native natural enemies. The increasing demand for pesticide-free, high quality vegetable produce year-round and the existing certification schemes make it very likely that the use of biocontrol agents will continue to increase in China.

Human papillomavirus infection is a major health problem and caused substantial benign and malignancy diseases among female and male worldwide. We aim to investigate the epidemiology of high-risk human papillomavirus (HR-HPV) and related diseases in Suzhou population. As well as evaluating the potential benefit of a nine-valent HPV vaccine (regardless of HPV-6 and -11) in Suzhou. A total of 40,108 people aged 13-89 years were retrospectively examined by database retrieval from 2010 to 2015. Thirteen genotypes (16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, and 66) of HR-HPV were detected using Tellgenplex™ xMAP™ HPV DNA Test assay. The overall prevalence of HR-HPV was 21.1%, the female and male account for 96.4% and 3.6%, respectively. The infection rate among male (25.6%, 367/1,432) was significantly higher than that among female (20.9%, 8,100/38,676), X

The polytetrafluoroethylene (PTFE) matrix composites which filled with polyphenylene sulfide (PPS) fiber, poly-p-phenelenferephthalamide (PPTA) fibre or glass fiber (GF)) and graphite at various mass fractions were prepared by the processes of mechanical blending, compression molding and sintering. The mechanical properties of the composites, such as tensile strength, impact strength and hardness were investigated. The results show that tensile strength and elongation at break markedly decrease but elasticity increases by filling with fibers. Impact strength decreases by filling with PPS and GF, and the composite displays brittle characteristic. However, the impact strength rapidly increases by filling with PPTA fiber. Hardness increases with the fibers content increases, and decreases with graphite content increases. Filling graphite into PTFE has light effect on the impact and tensile strength of composites. The tribological properties of the composites were investigated on M-2000 wear tester at dry friction condition. The wear mechanism was also discussed and the wear surfaces were examined by SEM. The result indicates that fibers which diffused in PTFE matrix wind with PTFE molecule chain, and then form grid structure. The load-bearing capacity of composites can be obviously enhanced and the trend of block fragmentations slide is inhibited, so that the tribological properties are improved markedly.

The reactions of aniline with CO2and CS2were investigated in the presence of sublimed AlCl3under the mild conditions (room temperature and ambient atmosphere). Reasonable mechanism, electrophilic substitution of carbonium and nitronium, was also provided according to GC/MS analysis of the reaction products. The resulting N,N-diphenylurea (DPU, high selectivity of 92.5mol%) and N,N-diphenyl thiourea (DPTU, high yield and selectivity of 80.1mol% and 99.7mol%, respectively) were purified by recrystallizing from ethanol and identified by melting point, element analysis, GC/MS, FTIR, UV and1H NMR data.

A series of ZnO-Bi 2 O 3 -based varistor ceramics doped with 0–0.4 mol.% Sc 2 O 3 were prepared by high-energy ball milling and sintered at temperatures between 1000 and 1150 °C. X-ray diffractometry (XRD) and scanning electron microscopy (SEM) were applied to characterize the phases and microstructure of the varistor ceramics. A DC parameter instrument for varistor ceramics was applied to investigate the electronic properties and V-I characteristics. The results showed that there were no changes in crystal structure with Sc 2 O 3 -doped varistor ceramics and that the average size of ZnO grain increased first and then decreased. The best electronic characteristics of the varistor ceramics prepared by high-energy ball milling were found in 0.3 mol.% Sc 2 O 3 -doped ZnO-Bi 2 O 3 -based ceramics sintered at 1000 °C, which exhibited a threshold voltage of 821 V/mm, nonlinear coefficient of 62.1 and leakage current of 0.16 μA.

Background: This study was aimed to investigate the genetic diversity and antibiotic resistance profi le of the nosocomial infection agent Acinetobacter baumannii from a medical intensive care unit (ICU) in a teaching hospital in Suzhou, China. Methods: The genetic relationship among A. baumannii isolates in an ICU was investigated using multilocus sequence typing (MLST). The antibiotic resistance pattern was determined by performing an antibiotic susceptible test, which included an agar dilution method and an E-test method. Resistant determinants, e.g., carbapenemase genes, metallo-βlactamases, and class 1 integron, were analyzed by specifi c PCR and DNA sequencing. Results: In the present study, 33 non-duplicate isolates were identifi ed as 5 existing sequence types (STs) (ST92, ST75, ST112, ST145, and ST345) and 1 new sequence type STn, which has a G-A mutation at nt268 on ropD40 of ST251. These results reveal limited diversity in carbapenem non-susceptible A. baumannii (CNSAb) isolates in our ICU, which are comprised of only 2 distinct STs, with ST92 and ST75 clustering into a clonal complex (CC) 92. Most CNSAb isolates (94.4%, 17/18) harbored the OXA-23 gene, while no carbapenem-susceptible A. baumannii (CSAb) isolates harbored it. In addition, 66.7% (22/33) isolates were positive for class 1 integrase, and gene cassette analysis showed there are 3 gene arrays among them, i.e., aacA4-catB8-aadA1 (77.3%, 17/22), aacA4 (22.7%, 5/22), and aacC1-orfX-orfX’-aadA1 (4.5%, 1/22). Conclusions: When all these data are combined, the antibiotic resistance and wide distribution of CNSAb isolates in our ICU are probably caused by expansion of the CC92 clone.

Y 2 O 3 -doped ZnO–Bi 2 O 3 thin films were fabricated on silicon substrates by sol–gel process and annealed in air at 750 °C for 1 h. Microstructure and electrical properties of ZnO thin films were investigated. XRD analysis shows that all peaks of ZnO thin films are well matched with hexagonal wurtzite structure of ZnO. SEM results present that the ZnO grain size decreases with the increase of dopant concentration, which means that rare earth doped can refine the grain size. The thickness of each layer is uniform and the value of thickness is about 80 nm. The nonlinear V – I characteristics with the leakage current of 0.46 μA, the threshold field of 110 V/mm and the nonlinear coefficient of 3.1 could be achieved when the films contain 0.2% (mole fraction) yttrium ion.

Dielectric properties and varistor performance of sol–gel prepared Ni-doped calcium copper titanate ceramics (CaCu 3 Ni x Ti 4 O 12+ x , x =0, 0.1, 0.2, 0.3) were investigated. SEM and XRD were used in the microstructural studies of the specimens and the electrical properties were investigated for varistors. XRD patterns show that the CCTO ceramics were single phase with no Cu-rich phase. SEM results indicated that the samples had smaller grain sizes than those synthesized by traditional solid-state reaction methods. The experimental results show that the highest dielectric constant and lower dielectric loss occur when x =0.2. When x =0.3, the lowest leakage current is obtained and the maximum value reaches 0.295; meanwhile, the lowest threshold voltage and nonlinear coefficient are found, the minimum values of them are 1326 V/mm and 3.1, respectively.

Ultrasonic was applied to assist the catalytic aquathermolysis reaction of heavy oil, and the effect of catalyst and ultrasonic on the physical and chemical properties of Shengli Gudong heavy oil was investigated. Compared to catalytic aquathermolysis reaction, the results of ultrasonic assisted catalytic aquathermolysis indicate that the viscosity of heavy oil is reduced by 86.2%, and the composite technology can further decrease the average molecular weight of heavy oil, increase the saturate and aromatic contents, decrease the resin and asphaltene contents, improve the mol ratio of nH/nC, and decrease the heteroatoms content of heavy oil. The results of dynamic simulation experiments show that in-situ ultrasonic assisted catalytic aquathermolysis exhibits good performance with the 53.91% heavy oil recovery and 80.5% viscosity reduction. The experimental results prove that the combination of ultrasonic and catalyst has a synergetic effect, which attributes to the reduction of viscosity and improvement of heavy oil quality.

Equal channel angular pressing (ECAP) of a quenched commercial pure titanium (CP-Ti) (grade 2) has been successfully performed at liquid nitrogen temperature with an imposed equivalent strain of about ∼0.5, and its microstructures, tensile properties and dislocation strengthening were investigated. High-resolution transmission electron microscopy (HRTEM) shows that the ECAPed CP-Ti presented a microstructure containing lattice distortions, dislocations, stacking defects and deformation twins. Tensile tests indicate that the ECAPed CP-Ti had yield strength of ~700 MPa (40 % higher than that of the unECAPed CP-Ti) and a high level of tensile ductility (~28%). X-ray diffractometer (XRD) data indicate that the ECAP processing not only broaden the XRD peaks significantly but also decreased texture considerably. The theoretical analysis by using Taylor equation based on the coherent diffraction domain size and the lattice micro-strain obtained from XRD line broadening analysis illustrates that ECAP-resulted dislocation made a strengthening contribution of about ~35.1 %.

The commitment of teachers of Physical Education Department in colleges are conducting PE course, training sports team, organizing sports science research, social sports service of the whole school etc. Methods are adopted, such as documentary, questionnaire investigation, and mathematical statistics etc., to have the gender, age, record of formal schooling status and in-service training status of PE faculty of colleges in Tianjin surveyed. According to the investigation, we can draw the conclusion that improving gender structure, cultivating scientific research team should be paid close attention to improve the teaching level when teachers are introduced in Tianjin universities. PE of colleges is not only considered to be an important component of higher education, whose quality is measured by Morality, intelligence and physique, but also an aspect which can not be ignored. The faculty of the department of Physical Education in colleges is liable for a series of important works such as Physical education curriculum teaching, sports training and sports research, students' extracurricular physical exercising guidance and services such as social sports. Many factors, such as high quality and structure of faculty resources and cultivating younger teachers, are playing an important influence on the future quality of education. In order to provide certain theoretical basis and theoretical support for the teaching management of public PE department of colleges in Tianjin, available suggestions to optimize the existing personnel structure and echelon construction could be contributed through the investigation.

The relationship between sintering process and vaporization of the Bi2O3 in ZnO-Bi2O3-based varistor ceramics was investigated. The phase and microstructure evolution during the sintering process were examined. The results show that the higher the sintering temperature or the longer the sintering time is, the more the Bi2O3 is volatilized. The heating rate has little effects on the Bi2O3 volatilized in ZnO-Bi2O3-based varistor ceramics. This is in accordance with the relative X-ray diffraction peak area ratio analysis. The results also show that the sintering temperature has the greatest impact on the vaporization of the Bi2O3, then followed by sintering time, and the effect of the heating rate is the minimum.

The whitefly Bemisia tabaci contains more than 35 cryptic species. The higher adaptability of Middle East-Asia Minor 1 (MEAM1) cryptic species has been recognized as one important factor for its invasion and displacement of other indigenous species worldwide. Here we compared the performance of the invasive MEAM1 and the indigenous Asia II 3 whitefly species following host plant transfer from a suitable host (cotton) to an unsuitable host (tobacco) and analyzed their transcriptional responses. After transfer to tobacco for 24 h, MEAM1 performed much better than Asia II 3. Transcriptional analysis showed that the patterns of gene regulation were very different with most of the genes up-regulated in MEAM1 but down-regulated in Asia II 3. Whereas carbohydrate and energy metabolisms were repressed in Asia II 3, the gene expression and protein metabolisms were activated in MEAM1. Compared to the constitutive high expression of detoxification genes in MEAM1, most of the detoxification genes were down-regulated in Asia II 3. Enzymatic activities of P450, GST and esterase further verified that the detoxification of MEAM1 was much higher than that of Asia II 3. These results reveal obvious differences in responses of MEAM1 and Asia II 3 to host transfer.

In this study, the brown planthopper (BPH), Nilaparvata lugens (Hemiptera: Delphacidae), cultured on Bt rice lines (T1C-19 with cry1C gene and T2A-1 with cry2A gene) and their parental rice MH63, were treated with a series of concentrations of triazophos and deltamethrin when they developed up to the third instar for the evaluation of the effects of Bt rice on BPH resurgence induced by pesticides. The results indicated that BPH nymphal duration decreased with the increasing concentration of deltamethrin, while no significant differences of BPH nymphal duration were observed on the same rice variety treated with the different concentrations of triazophos. Furthermore, the survival rate of BPH significantly declined and their fecundity significantly increased with the increasing concentration of insecticides. However, ecological fitness parameters of BPH including nymphal duration, survival rate, female adult mass, fecundity and egg hatchability were not significantly different among Bt and non-Bt rice varieties when they treated with the same concentration of insecticide. These results implied that no significant difference in the BPH resurgence induced by pesticides was observed among the two tested Bt rice varieties and their non-Bt parental rice variety.

Superoxide dismutases (SODs) are a group of important antioxidant defense enzymes. In this study, a putative extracellular Cu/Zn superoxide dismutase (ecCuZnSOD) complementary DNA was cloned and characterized from the whitefly, Bemisia tabaci. Quantitative polymerase chain reaction analysis showed that the expression level of BtecCuZnSOD was more than 10-fold higher in the invasive Middle East Asia Minor 1 (MEAM1) than in the native Asia II 3 species of the B. tabaci species complex. After exposure to low temperature (4 °C), the expression of Bt-ecCuZnSOD gene was significantly up-regulated in MEAM1 but not in Asia II 3. Furthermore, the expression level of B. tabaci intracellular CuZnSOD (Bt-icCuZnSOD), Bt-ecCuZnSOD and mitochondrial MnSOD (Bt-mMnSOD) was compared after transferring MEAM1 and Asia II 3 whiteflies from favorable (cotton) to unfavorable host plants (tobacco). On cotton, both CuZnSOD genes were expressed at a higher level in MEAM1 compared with Asia II 3. Interestingly, after transferring onto tobacco, the expression of Bt-ecCuZnSOD was significantly induced in Asia II 3 but not in MEAM1. On the other hand, while Bt-mMnSOD was expressed equally in both species on cotton, Bt-mMnSOD messenger RNA was up-regulated in MEAM1 on tobacco. Consistently, enzymatic activity assays of CuZnSOD and MnSOD demonstrated that CuZnSOD might play an important protective role against oxidative stress in Asia II 3, whereas MnSOD activation was critical for MEAM1 whiteflies during host adaptation. Taken together, our results suggest that the successful invasion of MEAM1 is correlated with its constitutive high activity of CuZnSOD and inducible expression of MnSOD under stress conditions.

Plant viruses transmitted by arthropods, as an important biotic factor, may not only directly affect the yield and quality of host plants, and development, physiological characteristics and ecological performances of their vector arthropods, but also directly or indirectly affect the non-vector herbivorous arthropods and their natural enemies in the same ecosystem, thereby causing influences to the whole agro-ecosystem. This paper reviewed the progress on the effects of plant viruses on herbivorous arthropods, including vector and non-vector, and their natural enemies, and on their ecological mechanisms to provide a reference for optimizing the management of vector and non-vector arthropod populations and sustainable control of plant viruses in agro-ecosystem.

Oral contraceptive (OC) use has been associated with alterations in carbohydrate metabolism. We examined the effect of OC use on the risk of diabetes among Chinese women. A nested case-control study was conducted among 57,130 women screened for diabetes at enrollment for the Shanghai Women's Health Study, a population-based cohort study of Chinese women aged 40-70 years in Shanghai, China. Included in this study were 259 women newly diagnosed with diabetes and 2072 age-matched controls (8 controls per case), randomly selected from women who tested negative for urine glucose. Multivariate-adjusted odds ratios (OR) and 95% confidence intervals (CI) were used to measure the strength of the association between OC use and diabetes risk. Overall, OC use was not associated with the risk of diabetes. Stratified analysis by menopausal status revealed a dose-response relationship between the duration of OC use and the risk of diabetes among premenopausal women (p for trend = 0.02), with a 3.2-fold elevated risk observed among those who used OC longer than 1 year. Risk of diabetes diminished with increasing time since last OC use (p = 0.02). Use of intrauterine devices was associated with a reduced risk of diabetes in both pre- and postmenopausal women (OR = 0.67, CI: 0.48-0.93). These findings suggest that recent use (within 5 years) and continued use (>1 year) of OCs may increase the risk of diabetes among Chinese women. However, the attributable risk for diabetes among OC users in the general population, if confirmed by further studies, appears to be small.