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The rapid development of coastal economies has aggravated the problem of pollution in the coastal water bodies of various countries. Numerous incidents of massive-scale marine life deaths have been reported because of the excessive discharge of industrial and agricultural wastewater. To investigate the diffusion of typical pollutants after discharge, in this study, a multi-process fusion simulation analysis model of pollutants under the action of ocean currents was established based on the concentration analysis method. Furthermore, key technologies involved, such as the parameter value, data selection, and visualization, were investigated. The iterative analysis and programming realization of three independent sub-processes, such as pollutant diffusion and transport, and the drift path and concentration distribution of pollutants after their discharge into the sea, were visualized. The case study revealed that the increase in the concentration of pollutants in the ocean was affected by the diffusion sub-process, and the transport sub-process plays a critical role in the long-distance transport of pollutants. The proposed method can provide technical support for marine environmental risk assessment and dynamic tracking of marine pollutants.

The reliability of fuel cell tram depends largely on the normal operation of on-board proton exchange membrane fuel cell (PEMFC) system. Therefore, timely and accurate fault diagnosis is necessary to further commercialize the fuel cell tram. And, a new fault diagnosis method BPNN-InceptionNet based on information fusion and deep learning is proposed in this paper. In this method, high-dimensional abstract features are extracted from the original measurement information by back propagation neural network (BPNN) and converted into feature maps for information fusion in feature level. Then the feature maps are transferred to a proposed Convolutional Neural Network (CNN) based on InceptionNet to realize fault classification. From the experiments, it is found that the kappa coefficient by BPNN-InceptionNet for the test set can reach 0.9884, which is better than that by BPNN, BPNN-VGG, and support vector machine (SVM) classifiers, meaning that the proposed method can achieve better diagnostic performance.

MicroRNA-186 (miR-186) and circular RNA (circRNA) circSEPT9 are two crucial players in cancer biology, while their roles in endometrial cancer (EC) are unclear. Our preliminary sequencing analysis revealed the potential crosstalk between circSEPT9 and miR-186 in EC.The expression levels of circSEPT9 and miR-186 in EC and paired non-tumor tissues from 64 EC patients were detected by RT-qPCRs. Correlation analysis was carried out with Pearson's correlation coefficient. The role of circSEPT9 in regulating the expression of miR-186 and the methylation of miR-186 gene was explored by RT-qPCR and methylation specific PCR (MSP), respectively. Cell invasion and migration were evaluated by Transwell assays.CircSEPT9 was upregulated in EC, and miR-186 was downregulated in EC. MiR-186 and circSEPT9 were inversely correlated across EC tissue samples, but not non-tumor samples. Overexpression of circSEPT9 decreased the expression levels of miR-186 and increased the methylation of miR-186 gene. CircSEPT9 increased cell invasion and migration and suppressed the role of miR-186 in inhibiting cell behaviors.Therefore, circSEPT9 is upregulated in EC and promotes cell invasion and migration by downregulating miR-186 through methylation.

Real-time tempo-spatial data is crucial in responding to urban emergencies. Limited by a revisiting period, spatial resolution, and data availability, traditional remote sensing data is often received too late to aid emergency management. This study proposes a real-time remote sensing approach that is based on the city skyline. In this approach, remote sensing sensors are deployed on super high-rise buildings (> 300 m), and real-time land observation products are obtained by following the regular remote sensing processing procedure. This remote sensing approach has advantages such as low-cost, easy sensor deployment and maintenance, no cloud interference, real-time observation, and a wide observation range. This novel remote sensing approach is an effective way to collect real-time tempo-spatial data on a small and medium scale. It can be used in urban flow (i.e., people and vehicle flows) monitoring, surface deformation detection, and urban night light analysis. This approach has great potential to aid in the rapid response to urban emergencies such as city fires, aggregated human activities, and floods.

To understand the effect of Cl doping in carbon dots, nitrogen-doped carbon dots (N-Cdots) and nitrogen and chlorine dual-doped carbon dots (Cl,N-Cdots) were fabricated by high-temperature carbonization and low-temperature concentrated acid (HCl) acidification of dried shaddock peel, respectively. The quantum yield of Cl,N-Cdots is about four times of that of N-Cdots and the size of Cl,N-Cdots is smaller than that of N-Cdots. Furthermore, since trinitrophenol (PA) and ClO− could effectively quench the fluorescence of Cl,N-Cdots, the fluorescence sensors for determining PA and ClO− was constructed, respectively. The linear range of PA and ClO− are 0.9–90 μM and 3.24–216 μM with the limit of detection of 37.1 nM and 2.88 μM, respectively. The proposed sensor was used to detect PA in Taiyuan tap water, Wutai tap water, Wutai rain water and Wutai river water samples with encouraging results. The as-constructed sensor was also used to detect ClO− in Taiyuan tap water and commercial disinfectants. Last but not least, Cl,N-Cdots was employed as an agent for A549 and HeLa cell-imaging, possessing optimal imaging effect and ultra-low cytotoxicity. Our results suggested that Cl,N-Cdots has promising applications in sensing, water monitoring, commodity supervision and cell-imaging.

Secondary organic aerosols (SOAs) are an important component of particulates, but whether biogenic SOAs (BSOAs) or anthropogenic SOAs (ASOAs) are the dominant contributors to haze pollution remains poorly characterized. In this study, particulate samples were collected from September 2014 to August 2015 at an urban site in Jinan, which is the capital of Shandong Province and a typical city in the North China Plain. The PM2.5 samples were analyzed for BSOA (isoprene (SOAI) and monoterpenes (SOAM)) and ASOA (aromatic (SOAA)) tracers. The concentrations of the SOAA tracer (1.1 ± 1.0 ng/m3) were lowest, and those of SOAI tracers (41.8 ± 86.2 ng/m3) were highest, with the concentrations of SOAM tracers (19.4 ± 9.9 ng/m3) being intermediate. The SOAI tracers were more abundant in the summer and less abundant in the winter. Both SOAI and SOAM increased with increasing ozone level but decreased with increasing NOx level. Correlation analysis revealed a good correlation between 2,3-dihydroxy-4-oxopentanoic acid and levoglucosan levels in three seasons. These results suggested that biomass burning activities occurring in the NCP can enhance the emissions of aromatics and should be controlled, especially in the autumn and winter. SOA tracers were classified according to pollution degree, and the results showed that as pollution increases, the contributions of SOAA increase. These results indicate that reducing anthropogenic emissions is necessary to prevent SOA pollution, especially during heavy pollution episodes.

Air pollution in north China is still severe, although Chinese government has exerted great efforts to cut down pollutant emissions in the past decade. To understand the chemistry and sources of the haze particles in north China, PM 2.5 aerosols were collected in Beijing from January 7 to February 27, 2014, during which two haze episodes (haze I and haze II) occurred. The samples were analyzed for water soluble inorganic ions, trace elements, sugars, n -alkane, polycyclic aromatic hydrocarbons (PAHs), fatty acids, dicarboxylic acid, EC (elemental carbon) and OC (organic carbon). Our results showed that relative abundances of primary species such as sugars, PAHs and EC were more abundant on the clean days and the haze I period in Beijing, while secondary aerosols especially secondary inorganic aerosol (SIA)were more abundant in the haze II period. Source apportionment further showed that emissions from cooking (21.6%), road-dust (19.4%), coal combustion (17.8%) and biomass burning (15.4%) were the main sources of PM 2.5 during the clean days, while biomass burning (20.1%) and coal combustion (17.1%) were the main sources during haze I period. For the haze II period, vehicle exhausts (26.9%), secondary aerosol formation (26.6%) and industrial emission (19.1%) were the dominant sources of PM 2.5 . Our work suggests that it is indispensable to reduce the emissions from biomass burning and vehicle exhaust in Beijing in order to further mitigate the haze pollution.

Azithromycin (AZM) 1 is one of the most widely used antibiotics. AZM abuse is easy to cause great harm to human body, so developing a rapid and sensitive method to detect AZM is of great importance. Herein, 3-aminothiophenol as only reaction precursor, nitrogen and sulfur co-doped carbon quantum dots (N,S-CQDs) 2 were fabricated by one-step hydrothermal carbonization method. All characteristics demonstrate that N,S-CQDs possess good water solubility, high fluorescence stability and low cytotoxicity. Without being disturbed by amino acids and drugs, the most interesting finding is that AZM can efficiently quench the fluorescence of N,S-CQDs by a synergistic effect of electrostatic interaction and static quenching. A fluorescent probe for the detection of AZM was constructed with high selectivity and good sensitivity, achieving two linear ranges of 2.5–32.3 μM and 37.2–110 μM and a limit of detection of 0.76 µM. The proposed fluorescent method was used for the detection of AZM in cells with fulfilling results. More importantly, the fluorescent probe was successfully used to the detection of AZM in tablets and human urine with recovery rate and relative standard deviations of 98.2–104.8% and 0.04–3.46%, respectively, which was confirmed by the standard method of HPLC-UV. This finding illustrates the usefulness and feasibility of N,S-CQDs as an effective fluorescent probe for the detection of AZM in tablets and human urine, which is helpful for supervising and guiding pharmacy.

Sugars and biogenic secondary organic aerosols (BSOAs) are substantial components of particulate organic matter, which affects regional and global air quality and climate. Fine particulate matter (PM 2.5 ) samples were collected from 20 June to 30 July 2015 on a diurnal/nocturnal cycle in Yucheng, China in the North China Plain. The PM 2.5 samples were analyzed for sugars and SOA tracers derived from biogenic volatile organic compounds (BVOCs) and other compounds, such as water soluble ions, element carbon (EC), organic carbon (OC) and water soluble organic carbon (WSOC). The quantified organic components accounted for 4.7% and 0.4% of the OC and PM 2.5 , respectively. SOA tracer concentrations were weakly higher during the day (101.6 ± 61.7 ng m −3 ) than at night (90.2 ± 41.5 ng m −3 )( t = 0.610, P > 0.05), whereas sugar showed higher concentrations at night (227.0 ± 196.9 ng m −3 ) than during the day (177.9 ± 145.4 ng m −3 )( t = −1.329, P > 0.05). Anhydro sugar (mannosan, galactosan, and levoglucosan) were the main components of the measured sugars and accounted for 58.5% and 75.6% of the daytime and nighttime measurements. The levoglucosan/mannosan ratios were 20.2 ± 12.9 and 17.6 ± 9.1 for the daytime and nighttime samples, respectively, indicating that crop residues, herbaceous plants and hardwood were the dominant types of biomass burned in the Yucheng region. Isoprene SOA tracers exhibited the highest levels among the measured SOA tracers, followed by α -pinene SOA tracers. The concentration of BSOC estimated using the tracer method was 3.9–1817.5 ng C m −3 and accounted for 0.1–26.0% of the OC. A clear negative correlation ( r = 0.53) between isoprene-derived SOA and in-situ pH demonstrated that acid-catalyzed heterogeneous reactions can significantly enhance SOA mass. In addition, isoprene-derived SOA increased with the relative humidity (RH) when the RH was lower than 50%, whereas it decreased when the RH was higher than 50%.

On the basis of a conceptual passive containment cooling system design, one-dimensional codes, which can be applied to large dry concrete containment in nuclear power plants, are developed to analyze containment thermal-hydraulic characteristics under typical accident scenarios. In this paper, physical models and solution methods are introduced. Containment is geometrically modeled as a combination of a rising cylinder and a downward ring. It is assumed that the control volumes experience adiabatic conditions, except for the heat exchanger and breaks, and that there is no exchange of mass, momentum or energy between each volume in the rising channel and the corresponding volume in the downward ring at the same level. In the current research, we conservatively assume that the heat in the containment can only be transferred through the heat exchanger of a passive containment cooling system by natural circulation. Furthermore, the break is hypothetically set at the bottom center of the containment. Simultaneously, the responses of the containment are predicted by codes for the large LOCA (Loss of coolant accident) scenario. Under the same conditions, the natural circulation characteristics are also studied using the codes developed for the passive containment cooling system. The results may provide a basis for the design of a passive containment cooling system.

To understand the effect of Cl doping in carbon dots, nitrogen-doped carbon dots (N-Cdots) and nitrogen and chlorine dual-doped carbon dots (Cl,N-Cdots) were fabricated by high-temperature carbonization and low-temperature concentrated acid (HCl) acidification of dried shaddock peel, respectively. The quantum yield of Cl,N-Cdots is about four times of that of N-Cdots and the size of Cl,N-Cdots is smaller than that of N-Cdots. Furthermore, since trinitrophenol (PA) and ClO

Phosphorus and nitrogen dually-doped carbon quantum dots (PN-CQDs) were prepared from sucrose, 85% phosphoric acid and 1,2-ethylenediamine as the sources for carbon, phosphorus and nitrogen, respectively. The PN-CQDs possess good water solubility and favorable biocompatibility. The excitation/emission peaks are at 365/451 nm, but bright blue, green, or red emissions are found depending on whether the excitation wavelengths of the laser are set to 408 nm, 488 nm, or 543 nm, respectively. Fluorescence is quenched by both vitamin B12 (VB12) and Co(II) by a combination of inner filter effect and static quenching. The PN-CQDs are shown to be useful nanoprobes for determination of VB12 and Co(II). Response to VB12 is linear in the range of 2.0–31 μM. The response to Co(II) is linear in two ranges, viz. from 1.7–12 μM and from 28 to 141 μM. The limit of detection of VB12 and Co(II) are 3.0 nM and 29.4 nM, respectively. The nanoprobe was successfully applied to the analyses of VB12 in drug samples and of Co(II) in spiked water samples, and it gave satisfactory results. The nanoprobe was also applied to the determination of VB12 and Co(II) in human hepatocarcinoma cells (type SMMC7721), human pulmonary epithelial cells (type BEAS-2B), human adenocarcinoma cells (type A549), and human pheochromocytoma cells (type PC12), respectively.

Simulating investigations are carried out to study the steady-state performances, the pressure resistance distributions and the scaling methods of the single-phase and flashing-induced two-phase flow in the open natural circulation system, which is designed for the passive containment cooling system. The results show that the steady-state mass flow rate changes with the heat transfer regularly both in the single-phase and flashing-induced two-phase flow under a certain inlet subcooling. From the sensitivity analysis, it can be found that the riser height only has impact on the single-phase flow but has little influence on the flashing-driven two-phase flow. Both increasing the diameters of the riser and downcomer can enhance the flow and heat transfer in sing-phase and two-phase flow when keeping the structure of the heat exchanger unchanged, but the influence degree for each flow type is different. The flow resistance distributions of the loops under different flow modes have been studied to provide the foundation for improving the heat transfer capacity by choosing the structural parameters reasonably. The pressure resistance distribution of the steady single-phase flow only relates to the geometrical, but the pressure resistance distribution of the two-phase flow relates both to the pipe diameters and to the external conditions. The acceleration pressure resistance in the riser section is the main resistance under the higher-quality two-phase conditions. Therefore, the influence of the riser diameter on the flashing-induced two-phase flow is far greater than that of downcomer diameter and the most effective method to improve the two-phase flow and heat transfer is to increase the diameter of the riser. Finally, the scaling analysis is performed for the penetration and economy considerations after selecting the optimal dimensions. The scaling of the cold and hot sections is considered separately to insure the driven force of the system unchanged, and different scaling criterions are given for the single-phase and flashing-induced two-phase flow according to the analyses of the pressure resistance distributions. The results show that the scaling criterion of the two-phase flow can deal with the scaling problem accurately both in the single-phase and two-phase flow. However, the scaling criterion of the single-phase flow only can solve the single-phase scaling problem, but it will overestimate the operating results in the scaling model.

Simulating investigations are carried out to study the resistance characteristics and flow instability during the start-up of the open natural circulation system, which is designed for the passive containment cooling system. Four different flow modes can be found during the start-up process: stable single-phase flow, flashing-induced intermittent flow, flashing-induced sinusoidal flow and stable two-phase flow. Flashing occurring in the riser section is the only phase-change phenomenon in this study. The flow resistance distributions of the loops under different flow modes have been studied to provide the foundation for choosing the structural parameters reasonably to improve the heat transfer capacity. The results show that the system has nearly the same resistance distribution in the steady single-phase flow under different containment conditions. The acceleration pressure resistance in the riser section is the main resistance in two-phase flow. The two-phase heat removal capability can be improved by increasing the diameter of the riser partially, of which the expansion section only needs to satisfy the condition that the length of expansion section is longer than that of flashing. The effects of the tube diameters and the inlet and outlet resistances of the heat exchanger on the flashing-induced instability region also have been studied. The results indicated that increasing the diameter of downcomer and decreasing the riser diameter can reduce the flow instability region. However, both increasing the inlet and outlet resistance coefficient of the heat exchanger will enlarge the flashing-induced instability region.

A code based on the homogeneous equilibrium model for two-phase flow was developed to simulate the transient behaviors of the open natural circulation system with a large tank as the heat sink. Detailed mechanism analyses with regard to different behaviors are conducted, and then some sensitivity studies of the systematic parameters are performed. The results show that the natural circulation system may experience several difference types of the operating periods. The response time of the system from the standing-by state to starting up is quite short and less than 200 s. In the single phase flow period, the upper tank has great influence on the trend of the flow rate evolution because of the stratification of the water in it. During the period of transition process from the single-phase to two-phase flow, flashing and flashing-induced oscillation may take place in the adiabatic section. With the increase of the temperature of fluid entering into the heat exchanger, the flow oscillation is weakened and then disappears gradually. When the temperature of fluid in the tank reaches the saturation temperature under atmospheric pressure and remains unchanged, the approximate stable two-phase flow and flashing are achieved. It can be seen from the sensitivity studies that increasing the heat transfer coefficient outside the heat transfer tube and the temperature in the containment can enhance the flow of the system both in single-phase and two-phase conditions. Increasing the height of the adiabatic section can only accelerate the single-phase flow rate, but has little influence on the two-phase flow and the flashing region during the long-term operation condition.

The purpose of this study was to prospectively evaluate the reproducibility of the proton density fat-fraction (PDFF) of the liver using the IDEAL algorithm, a quantitative confounder-corrected chemical-shift-encoded MRI method. Data were obtained from 15 volunteers on four different days. The first and the third examinations were conducted on scanner one with one-week intervals, while the second and the fourth tests were performed on scanner two with same time interval. For each test, two MR scans were performed, one before and one after a meal. Regions-of-interest measurements were manually calculated to estimate the PDFF in the right and left lobes on the PDFF images. Reproducibility was measured using the intra-class correlation coefficient (ICC). The ICCs of the PDFF in the right and left lobes were 0.935 and 0.878, respectively. The intra-scanner ICCs of the right lobe before and after a meal or at a one-week interval were 0.924 and 0.953, respectively. The inter-scanner ICCs of PDFF the next day and at a one-week interval were 0.920 and 0.864, respectively. The PDFF of liver derived from IDEAL demonstrated high intra- and inter-scanner measurement reproducibility. The PDFF of the right lobe before a meal was more reproducible than after-meal measurements.

The clinical pathway execution is a complex system engineering related to multidisciplinary or multi-department collaboration such as examination, laboratory test, operation, nursing, etc. This paper has proposed a multi-agent based simulation method from the hospital system level, and some key technologies including simulation model specification for hospital system, patient behavior model specification based on clinical pathway, and the multi-agent simulation model scheduling mechanism are discussed. Keywords-clinical pathway; multi-agent simulation; simulation model specification; patient behavior modeling; simulation scheduling

An open natural circulation system applied to the passive containment cooling system is proposed for the large dry double-wall concrete containment after severe accidents. In order to investigate the operating behaviors of the open loop, a numerical code is developed to simulate the transient flow characteristics from the startup to the long-term operation. The results show that the open system may experience such four stages as startup process, quasi-steady single-phase flow, transition stage and quasi-steady two-phase flow. Flashing is the dominated factor in the last two flow phases. Additionally, the effects of some systematic parameters on the mass flow rate are analyzed in detail. Both increasing the condensation heat transfer coefficient and the containment temperature can enhance the flow effectively whichever stage the system operates in. But the the initial fluid temperature can only affect the duration of the single-phase flow but has little impact on the mass flow rate. Moreover, greater riser height can lead to bigger single-phase flow rate, but nearly has no influence on the long-term two-phase flow and the flashing region.Copyright © 2014 by ASME

The containment is an ultimate and important barrier to mitigate the consequences after the release of mass and energy during such scenarios as loss of coolant accident (LOCA) or main steam line break (MSLB). In this investigation, a passive containment cooling system (PCCS) concept is proposed for a large dry concrete containment. The system is composed of series of heat exchangers, long connecting pipes with relatively large diameter, valves, and a water tank, which is located at the top of the system and serves as the final heat sink. The performance of the system is numerically studied in detail under different conditions. In addition, the influences of condensation heat transfer conditions and containment environment temperature conditions are also studied on the behaviors of the system. The results reveal that four distinct operating stages could be experienced as follows: startup stage, single phase quasisteady stage, flashing speed-up transient stage, and flashing dominated quasisteady operating stage. Furthermore, the mechanisms of system behaviors are thus analyzed. Moreover, the feasibility of the system is also discussed to meet the design purpose for the containment integrity requirement. Considering the passive feature and the compactness of the system, the proposed PCCS is promising for the advanced integral type reactor.

Green fluorescent protein and a glycosylphosphatidylinositol (GPI) anchor containing the common core structure and a lipid chain were synthesized and then coupled together under the promotion of bacterial sortase A (SrtA), which was the first example for the synthesis of a full-size GPI-anchored protein by SrtA, demonstrating that this can be a generally useful method for GPI-anchored protein synthesis.

Analogs of the human CD52 and CD24 antigens carrying the common core structure of glycosylphosphatidylinositol (GPI) anchors and the intact polypeptide sequences of CD52 and CD24 were chemoenzymatically synthesized. CD52 and CD24 proteins were obtained by solid-phase peptide synthesis and then coupled to chemically synthesized GPI anchors under the influence of a bacterial enzyme, sortase A, to afford the target molecules in good yields.

The distribution and source of the solvent-extractable organic and inorganic components in PM2.5 (aerodynamics equivalent diameter below 2.5 microns), and PM10 (aerodynamics equivalent diameter below 10 microns) fractions of airborne particles were studied weekly from September 2006 to August 2007 in Beijing. The extracted organic and inorganic compounds identified in both particle size ranges consisted of n-alkanes, PAHs (polycyclic aromatic hydrocarbons), fatty acids and water soluble ions. The potential emission sources of these organic compounds were reconciled by combining the values of n-alkane carbon preference index (CPI), %waxC(n), selected diagnostic ratios of PAHs and principal component analysis in both size ranges. The mean cumulative concentrations of n-alkanes reached 1128.65 ng/m3 in Beijing, 74% of which (i.e., 831.7 ng/m3) was in the PM2.5 fraction, PAHs reached 136.45 ng/m3 (113.44 ng/m3 or 83% in PM2.5), and fatty acids reached 436.99 ng/m3 (324.41 ng/m3 or 74% in PM2.5), which resulted in overall enrichment in the fine particles. The average concentrations of SO4(2-), NO3(-), and NH4(+) were 21.3 +/- 15.2, 6.1 +/- 1.8, 12.5 +/- 6.1 microg/m3 in PM2.5, and 25.8 +/- 15.5, 8.9 +/- 2.6, 16.9 +/- 9.5 microg/m3 in PM10, respectively. These three secondary ions primarily existed as ammonium sulfate ((NH4)2SO4), ammonium bisulfate (NH4HSO4) and ammonium nitrate (NH4NO3). The characteristic ratios of PAHs revealed that the primary sources of PAHs were coal combustion, followed by gasoline combustion. The ratios of stearic/palmitic acid indicated the major contribution of vehicle emissions to fatty acids in airborne particles. The major alkane sources were biogenic sources and fossil fuel combustion. The major sources of PAHs were vehicular emission and coal combustion.

In this paper, a closed loop concept, which is composed of two heat exchangers with same scale, pipes, valves and one tank, has been developed as a passive containment cooling system for a large dry concrete containment. The system is designed to maintain the containment integrity by taking the heat drained into the containment following a severe accident, e.g. LOCA or MSLB. Under different conditions in containment, the system may operate in single phase mode or two phase mode. According to the design limitation of containment, the fixed temperature boundary condition is applied to the system analysis. We have developed the codes for the analysis of the system by ourselves. The operating behaviors of the system are studied numerically from startup to long term operation. In the light of the fact that the fraction of steam in the containment may be changing during the accident scenario, it is reasonable that the heat transfer coefficient will be different. Therefore, the sensitivity analysis of the heat transfer coefficient is also performed. Based on the results and corresponding analysis, it can be concluded that the system may be utilized to meet the design purpose for the containment integrity requirement.Copyright © 2013 by ASME

This paper investigates the complete periodic synchronization of memristor-based neural networks with time-varying delays. Firstly, under the framework of Filippov solutions, by usingM-matrix theory and the Mawhin-like coincidence theorem in set-valued analysis, the existence of the periodic solution for the network system is proved. Secondly, complete periodic synchronization is considered for memristor-based neural networks. According to the state-dependent switching feature of the memristor, the error system is divided into four cases. Adaptive controller is designed such that the considered model can realize global asymptotical synchronization. Finally, an illustrative example is given to demonstrate the validity of the theoretical results.

A new method was developed for site-specific modifications of liposomes by proteins via sortase A (SrtA)-mediated transpeptidation reactions. In this regard, the enhanced green fluorescent protein (eGFP) was biologically engineered to carry at its polypeptide C-terminus the LPATG motif recognized by SrtA and used as the protein donor for linking to liposomes that were decorated with phospholipids carrying a diglycine motif as the other SrtA substrate and the eGFP acceptor. Under the influence of SrtA, eGFP was efficiently attached to liposomes, as proved by analyzing the enzymatic reaction products and the resultant fluorescent liposomes. It was observed that increasing the concentration and the distance of the diglycine motif on and from the liposome surface could significantly improve the efficiency of liposome modification by proteins. It is anticipated that this strategy can be widely useful for the modification of liposomes by other proteins.

A chemoenzymatic method was developed for the synthesis of macrocyclic peptides and glycopeptides. Sortase A was found to mediate either head to tail cyclization or oligomerization and then head to tail cyclization of peptides and glycopeptides, depending on the peptide length, to produce 15-mer or higher cyclic peptides and glycopeptides.

Several peptides/small proteins and glycosylphosphatidylinositol (GPI) derivatives were synthesized and compared as substrates of sortase A (SrtA), a bacterial transpeptidase, for enzymatic coupling. It was observed that peptides containing the LPKTGGS and LPKTGGRS sequences as sorting signals at the peptide C-terminus were effectively coupled to GPI derivatives having one or two glycine residues attached to the phosphoethanolamine group at the nonreducing end. This reaction was employed to prepare several analogues of the human CD52 and CD24 antigens, which are naturally GPI-anchored glycopeptides/glycoproteins. It was further observed that the trisaccharide GPI analogues 5 and 6 were better SrtA substrates than monosaccharide GPI analogue 4, suggesting that steric hindrance of the GPI analogues does not affect their peptidation reaction mediated by SrtA. Therefore, this synthetic strategy may be useful for the preparation of more complex GPI-anchored peptides, glycopeptides, proteins, and glycoproteins.

It is demonstrated that sortase A (SrtA) can catalyze efficient coupling of peptides to GPI analogues with a glycine residue attached to the phosphoethanolamine moiety at the nonreducing end to form GPI-linked peptides. This represents the first chemoenzymatic synthesis of GPI-peptide conjugates and is a proof-of-concept for the potential application of SrtA to the synthesis of more complex GPI-anchored peptides/glycopeptides and GPI-anchored proteins/glycoproteins.

MUC1 glycopeptide was efficiently coupled to glycosylphosphatidylinositol (GPI) derivatives by sortase A (SrtA), verifying that SrtA can accept sterically hindered glycopeptide as substrate for ligation with GPIs. This work has established a practical method for the chemoenzymatic synthesis of GPI-linked glycopeptides.

Camptothecin (CPT) is a potent inhibitor of DNA topoisomerase I with a wide spectrum of anti-tumor activity. Relatively little information is available regarding the relation of known topoisomerase-mediated DNA damage with other intracellular pathways. To gain an insight into the intracellular molecular mechanisms of Topoisomerase I inhibitor camptothecin-mediated DNA damage leading to cell death, we used a high-density cDNA microarray to assess sensitive early gene expression profiles in SGC7901 (gastric cancer), Hela (cervical adenocarcinoma), K562 (chronic myelogenous leukemia) and HL60 (promyelocytic leukemia) tumor cells stimulated with camptothecin for 1 h at the concentrations of GI50 (50 % growth inhibition after 24 h of treatment). Analysis of the differentially expressed genes obtained 29 response genes common to all four cell lines. Moreover, these cell lines also shared the direction of regulation. Most of these common response genes were functionally related to cell proliferation or apoptosis, and some of them were involved in ATM (ataxia-telangiectasia mutated) and ATR (ATM-and Rad3 related) checkpoint pathways, JNK (c-Jun N-terminal kinase) pathway, the survival phosphatidylinositol (PI) 3 kinase-Akt-dependent pathway, mitochondrial cell death pathway, endoplasmic reticulum (ER)-related cell death pathway, and to ubiquitin/proteasome dependent protein degradation pathway. The data provides evidence for a linkage between topoisomerase-mediated DNA damage and intracellular signaling events, which may facilitate our understanding of the camptothecin mediated molecular mechanisms of action.

The concentration of atmospheric CO2 in Beijing increased rapidly at a mean growth rate of 3.7% · a−1 from 1993 to 1995. After displaying a peak of (409.7±25.9) μmol · mol−1 in 1995, it decreased slowly. Both the almost stable anthropogenic CO2 source and increasing biotic CO2 sink contribute to the drop of CO2 concentration from 1995 to 2000. The seasonal variation of CO2 concentration exhibits a clear cycle with a maximum in winter, averaging (426.8±20.6) μmol · mol−1, and a minimum in summer, averaging (369.1±6.1) μmol·mol−1. The seasonal variation of CO2 concentration is mainly controlled by phenology. The mean diurnal variation of atmospheric CO2 concentration for a year in Beijing is highly clear: daily maximum CO2 concentration usually occurs at night, but daily minimum CO2 concentration does in the daytime, with a mean diurnal difference more than 34.7 μmol·mol−1. It has been revealed that the interannual variations of atmospheric CO2 concentration in winter and autumn regulated the interannual trend of atmospheric CO2, whereas the interannual variation of CO2 concentration in summer affected the general tendency of atmospheric CO2 in a less degree.