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Construction accidents can easily cause massive casualties and property losses. This research uses machine learning technique to analyze 16 critical factors and assess the impact of diverse combinations of factors on the performance of predicting the severity of construction accidents. The prediction is carried out with eight algorithms: Logistic regression, Decision tree, Support vector machine, Naive Bayes, K-nearest neighbor, Random forest, Multi-Layer Perceptron and AutoML. The results show that (1) Based on 16 accident factors, Naive Bayes and Logistics regression achieve the best F1-Score of 78.3 % on raw data set. (2) With AutoML method, severity classification can achieve an average F1-Score of 84 %. (3) The analysis of the confusion matrix shows that the subjective classification of the original data and specific unusual accidents are the sources of misprediction. (4) The “Type of accident” and “Accident reporting and handling” are the most critical factors and “Emergency management” and “Safety training” are important subsystems, both of which greatly affect the severity of the accident. (5) Based on the Decision tree, a set of assessment rules for the severity of construction accidents can be extracted. The prediction models and conclusions obtained from this study can be used to enhance the experience of safety professionals in urban construction and to make the safety intervention measures more efficient.

This paper presents experimental studies on the unsteady hydrodynamic loads (forces and moments) on a Tension-Leg Platform (TLP) due to the action of a steady current at high Reynolds numbers ( R e ) in a high-speed cavitation water tunnel. Five current incidence angles ( θ ) ranging from 0° to 45° are selected for the present tests. The achieved Reynolds numbers of 9 . 5 × 1 0 4 ≤ R e ≤ 5 . 7 × 1 0 5 span from the subcritical to supercritical flow regimes. The experimental results show that at R e 2 . 2 × 1 0 5 , the mean streamwise force coefficient C ¯ x increases as R e grows for 0° current incidence, while it reduces slightly for 15°, 22 . 5 ∘ , 30° and 45° current incidences. At R e ≥ 2 . 2 × 1 0 5 , C ¯ x remains roughly unvaried with R e for each current incidence angle. The fluctuating streamwise force coefficient C x ′ drops gradually as R e increases from 9 . 5 × 1 0 4 to 2 . 2 × 1 0 5 , and then they rise slightly for all the current incidences. The fluctuating transverse force coefficients ( C y ′ ) in the supercritical regime ( 2 . 2 × 1 0 5 R e 5 . 7 × 1 0 5 ) are less than those in the subcritical regime ( 9 × 1 0 4 R e 1 . 5 × 1 0 5 ), which is independent of θ . The fluctuating yaw moment coefficients ( C M z ′ ) show a declining trend with the increase of R e for 0°, 15°, 22 . 5 ∘ and 30° current incidences. In the supercritical regime, the measured C y ′ and C M z ′ for 22 . 5 ∘ current incidence are larger, comparing with those for the other current incidence angles. In addition, the correlations between forces and yaw moment indicate that the fluctuating transverse force is the main contribution to the fluctuating yaw moment. Furthermore, the effect of the immersed column height ( H ) on the forces and yaw moment is examined. It is found that, in the supercritical regime, generally C y ′ and C M z ′ grow as H ∕ D (where D is the column diameter) increases from 1.0 to 1.57.

The reliability of pipes, tubes and liquid tanks (cylinders) is of paramount significance to our life. The typical way to examine the ability of those structures to undergo plastic deformation is to apply a flattening test. In this paper, we used the Gurson-Tvergaard-Needleman damage model and finite element simulations to capture the flattening of a tube made of typical pipe materials. We demonstrated how the tube thickness, radius, and length would affect the critical displacement where tube failure initiates. For flattening with platens, the failure displacement first increases with tube length and reaches a peak value, and it then decreases and converges to a constant value for a particular geometry. The failure initiates at the two edges of short tubes, but shifts to the center in intermediate tubes where the failure displacement maximizes. Failure then always starts from the middle in even longer tubes. In contrast, flattening with indenters exhibits two peaks in the compressible displacement vs. tube length curve. In the end, we proposed effective experimental strategies to obtain the intrinsic ability of tubes under plastic deformation. The results reported here could be employed to characterize the mechanical properties of materials for pipes, tubes and tanks, and they could also be applied to guide the engineering design of such structures.

The three-dimensional (3D) distribution of radiological dose rate is important for assessing the biological hazard of atmospheric radionuclides in the environment. Because of the complexity of such scenarios, existing methods only estimate one- or two-dimensional dose rates, and trade accuracy and generality for acceptable speed. The lack of efficient 3D estimation methods prevents the 3D biological effect assessment of atmospheric radionuclides. This paper presents a 3D dose rate field estimation method that accelerates the computation by several orders of magnitude without loss of accuracy or generality. This method reformulates the time-consuming 3D integral in the dose rate model as a convolution and uses a fast Fourier transform to accelerate its solution. The convolution form provides a new receptor-oriented insight into dose rate estimation that can flexibly describe the radiological response of biological tissues. The proposed method makes no approximations or assumptions, so it is accurate and applicable to arbitrary atmospheric dispersion models and radionuclide distributions. Our approach is validated by both simulations and a field experiment. The results show that the proposed method is accurate and fast in both simple and highly complex air dispersion scenarios, and provides better quantitative and qualitative agreement with the experimental data than RIMPUFF's tabulated method. This method bridges the long-standing gap between the refined 3D atmospheric radionuclide transport modelling and the corresponding 3D biological hazard evaluation.

In this paper, a modified Monte-Carlo tree search (MCTS) algorithm is proposed to solve two-sided assembly line balancing problem (TALBP). Firstly, a brief review on TSALBP is provided. Then the modified MCTS algorithm is introduced and its main features are also pointed out. The test is performed on the well-known benchmark set of problem instances. Experiments results show that our new algorithm significantly outperforms existing results, especially for large problems.

The engineer-to-order (ETO) production strategy plays an important role in today’s manufacturing industry. This paper studies the multi-project scheduling in assembly process of ETO products. The multi-project scheduling problem is to schedule tasks of different projects under many constraints and assign hierarchical workers to each task. We develop a mathematical model to represent the problem. In order to solve with the minimization of makespan as the objective, we propose a hybrid algorithm combining particle swarm optimization (PSO) and Tabu search (TS). The improved PSO is designed as the global search process and the Tabu search is introduced to improve the local searching ability. The proposed algorithm is tested on different scale benchmark instances and the case that uses industrial data from a collaborating steam turbine company. The results show that the solution quality of the hybrid algorithm outperforms the other three algorithms proposed in the literature and the experienced project manager.

Wet deposition, including both in- and below-cloud scavenging, is critical for the atmospheric transport modeling of 137Cs following the Fukushima Daiichi Nuclear power plant (FDNPP) accident. Although intensively investigated, wet deposition simulation is still subject to uncertainties of meteorological inputs and wet scavenging modeling, leading to biased 137Cs transport prediction. To reduce the dual uncertainties, in- and below-cloud wet scavenging schemes of 137Cs were simultaneously integrated into Weather Research and Forecasting-Chemistry (WRF-Chem), yielding online coupled modeling of meteorology and the two wet scavenging processes. The integration was performed using 25 combinations of different in- and below-cloud schemes, covering most schemes in the literature. Two microphysics schemes were also tested to better reproduce the precipitation. The 25 models and the ensemble mean of 9 representative models were systematically compared with the below-cloud-only WRF-Chem model, using the cumulative deposition and atmospheric concentrations of 137Cs measurements. The results reveal that, with the Morrison's double moment cloud microphysics scheme, the developed models could better reproduce the rainfall and substantially improve the cumulative deposition simulation. The in-cloud scheme is influential to the model behaviors and those schemes considering cloud parameters also improve the atmospheric concentration simulations, whereas the others solely dependent on the rain intensity are sensitive to meteorology. The ensemble mean achieves satisfactory performance except one plume event, but still outperforms most models.

The precipitating behavior of Cu-riched particles during isothermally aging and its effect on hardness and damping capacity of Fe-16Cr-2.5Mo-1.0Cu damping alloy have been investigated by atom probe tomography (APT) and scanning transmission electron microscopy (STEM). The results show that aging at temperature range from 400 °C to 700 °C has minor influence on grain size. During aging at temperature below 400 °C, the supersaturated Cu dose not precipitate out. While aging temperature is 450 °C, a relatively small number of Cu-riched particles can be observed and the particle radius is small (1.5 ± 0.56 nm). With a further increasing aging temperature, the Cu-riched particles increase to 3.21 ± 0.52 nm at 550 °C and further grow to 12.88 ± 2.02 nm at 700 °C. As compared with 450 °C, the particle number increases significantly at 550 °C, and then decreases at 700 °C. Due to the stable grain size and no precipitate, the hardness keeps constant below 400 °C. With a further increasing aging temperature, the hardness increases gradually and reaches peak value aging at 600 °C due to the increase of Cu-riched particle number. The damping capacity significantly depends on particle. Once there appear Cu-riched particles, the damping capacity decreases obviously. During aging, both hardness and damping capacity of the alloy can keep stable when temperature is below 400 °C.

Over the past several decades, the high frequency of oil pipeline accidents has drawn substantial attention around the world. Many oil pipeline accident analysis models have been established based on the event tree method, the Bayesian network method and Computational Fluid Dynamics (CFD) simulation models. Considering the disadvantages of current models for comprehensively representing the incident evolution process and quantitative analysis for consequences, this paper proposes a probabilistic analysis model for oil pipeline accidents that integrates three methods the event tree (E), the incident evolution diagram (E) and the Bayesian network (B). Therefore, the model is called the “EEB model”. The EEB model can identify the initial event and secondary events, illustrate the accident evolution path, identify the key influencing factors, analyze their effects, and calculate the probabilities of different consequences of oil pipeline network accidents. Compared with other models, the EEB model considers more factors, such as key environmental conditions and the emergency response. Probabilistic analysis of different consequences, including casualties, economic losses, environmental pollution and the influence on social order, can be obtained. For a general scenario of an oil pipeline network accident, the probabilities for different consequences are 71.3% for “less than 5 persons affected”, 68.2% for “less than 10 million RMB lost”, 50.4% for “less than 1 km2 of water pollution” and 59.5% for “influence on social order of less than 100 persons”. The risk for the accident can be estimated by assuming the probability of the initial event as P. The model also denotes the emergency targets to be achieved and the response missions to be executed. Based on this information, a response plan can be developed for decision making. Since the incident evolution process is complex, the effects of the influencing factors should be analyzed. The EEB model highlights the significant influences of the water area (e.g., the probability of “10–50 km2 of water pollution” decreases from 38.7% for “near and large” water bodies to 17.4% for “far and small” water bodies) and the emergency response (e.g., the probability of “50–100 million RMB economic loss” increases from 11.5% for an “effective” response to 29.3% for a “poor” response). The probabilistic analysis obtained by the EEB is more comprehensive than those of other models, and the results can be used for risk analysis, decision making and effect analysis of oil pipeline networks.

Five Fe-16Cr-2.5Mo damping alloys with different Cu contents (0%, 0.25%, 0.5%, 1.0% and 2.0%) were prepared. The microstructure was observed by scanning transmission electron microscopy (STEM) and the damping behavior was measured by using a dynamic mechanical analyzer (DMA). The results show that the grain size of experimental alloy with (0.25–1.0%) Cu was refined compared with the 0Cu alloy. The Cu element is fully dissolved in the matrix and there are no Cu precipitates and carbides observed. Although the internal stress increases because of Cu addition, the damping capacity of the 0.5Cu and 1.0Cu alloys has been significantly improved. The reason of damping improvement is that the magnetic domain structure is strongly modified. Meanwhile, the strength was improved gradually due to the Cu solid solution strengthening and grain refining. In the 2.0Cu alloy, lots of Cu-riched particles appeared in the matrix. These Cu precipitates with 10–15 nm in size are spherical and homogeneously distributed, which strongly induce strength improvement through precipitation strengthening. On the contrary, the elongation and impact energy of the 2.0Cu alloy decrease sharply. In addition, lots of Cu precipitates will significantly decrease the damping capacity by hindering the mobility of domain walls.

A novel microcapsule with a reverse bumpy ball structure was formed to scavenge the reactive oxygen species (ROS) derived from an inorganic particulate ultraviolet (UV) filter. The microcapsule was composed of zinc oxide nanoparticles (ZnO NPs) and cerium dioxide (CeO2) shell, with a number of ZnO NPs encapsulated within the CeO2 hollow microsphere. The UV shield performance, the ability to remove the generated ROS, and the cytotoxicity of microcapsule under various conditions were evaluated through a series of in vitro experiments. The results show that the design not only improves the UV shielding performance of the ZnO NPs, but also significantly reduces the self-generated ROS by being confined in the hollow structure and the antioxidative action of the CeO2 shell. In general, a simple and effective strategy for removing the produced ROS from inorganic UV filters without compromising their shielding capacity was presented. This new microcapsule opens up a new avenue for the rational design of next-generation UV filters with minimal side effects.

Some extreme cold events have occurred in the past few years. Human perceptual responses and cognitive performances when exposed to extremely cold environments could be significantly influenced. Impaired cognition can result in human errors and other cascading impacts. This paper aims to investigate human thermal perception and cognitive performance in an extremely cold environment in a climatic chamber. The study involved and exposed twelve male participants who wore protective clothing (2.16 clo) to a −20 °C climate chamber. Critical parameters for evaluating human perceptual response and cognitive performance, including thermal sensation vote (TSV), thermal comfort vote (TCV), mood, health symptoms, and selective attention performance, were recorded and analyzed. The results showed that the TSV did not recover to the value before the cold exposure despite the subjects being rewarmed in a neutral environment for 40 min. The participants’ TSV reached the coldest after 20–25 min. Cold exposure increased discomfort, which required more than 40 min to recover. The extremely cold exposure resulted in increased tension, anger, confusion, decreased depression and fatigue. Anger and confusion had a strong correlation with tension-anxiety, and the correlation was stronger after recovery. The extremely cold exposure had a sustained impact on selective attention and heart rate. The reaction speed decreased by 36%. The results could be used to form recommendations to protect workers’ health and performance when exposed to extremely cold environments.

Thymol is one of the main essential oils derived from oregano with wide-ranging potential applications, such as antioxidation, anti-inflammation, and antibacterial properties. However, its low water solubility and bioavailability, as well as poor stability, have severely restricted its practical applications. Herein, deamidated zein nanoparticles loaded with thymol (DZTNPs) have been successfully prepared using the antisolvent precipitation approach. Particularly, a common alkaline deamidation method is used to pretreat zein as the particle precursor. Scanning electron microscopy, dynamic light scattering, zeta potential measurement, X-ray diffraction and differential scanning calorimeter have been used to characterize the resultant DZTNPs. It is worth noting that after freeze-drying, deamidated zein nanoparticles loaded with thymol have good redispersibility and physical stability stored at 4 °C. Furthermore, the as-prepared DZTNPs have greater antibacterial efficacy against E. coli and S. aureus than unencapsulated thymol for a longer period of time. Therefore, this study provides a viable vehicle for delivering hydrophobic active compounds, which is of significance in the application of food, cosmetics and pharmaceutics.

This paper focuses on the study of environmental risk assessment and comprehensive index model of disaster loss for COVID-19 transmission. Considering the five environmental vectors of carrier vulnerability, environmental instability of pregnancy and disaster, intensity of disaster-causing factors, disaster prevention and mitigation capacity and emergency prevention and control capacity and its 38 indicators, the correlation coefficient matrix and principal component expressions of each vector are established by principal component analysis, respectively, and the index model of each vector is established on the basis. Then, considering the index models of these five vectors, we established the disaster loss composite index model, which was used to conduct environmental risk assessment and disaster loss composite index analysis of the transmission of COVID-19 in Hubei Province during the period of January 21, 2020 to March 18, 2020. The empirical study showed that: (1) the risk index peaked from January 21 to January 23; (2) the risk index was at a low but volatile level from January 24 to March 14; (3) the risk index rose again slightly from March 15 and rose to another peak on March 16. These fluctuating, smooth and fluctuating processes of the comprehensive index of disaster losses of COVID-19 in Hubei Province are basically stable and consistent with the actual situation of the virus outbreak in the early stage, isolation and prevention and control in the middle stage, and resumption of work and production in the late stage. The study in this paper provides a scientific decision-making reference for the prevention and control of COVID-19 as well as emergency prevention and control measures.

This paper presents numerical studies on vortex-induced motions (VIM) of a multi-column floating oil and gas exploration platform. Numerical computations are performed using an improved delayed detached eddy simulation (IDDES) together with a moving grid approach. The transverse (sway) and yaw motion responses, motion trajectories, motion frequencies and power spectral density of motions are computed and analyzed systematically. After extensive comparisons with experiments, it is confirmed that the present numerical solutions using IDDES agree well with the experimental results and are better than those via delayed detached eddy simulation (DDES). The differences of transverse motion responses between computational results and experiments are less than 10% in the lock-in region. The numerical simulations reveal that the transverse VIM responses occur in a range of reduced velocities from 7.0 to 14.0 at H / D = 1.44 ( H and D are the column height and width, respectively). The largest nominal transverse amplitude, around 35 % of the column width, occurs for 22 . 5 ∘ current incidence. It is found that the VIM responses mainly perform along the platform diagonals for 1 5 ∘ , 22 . 5 ∘ and 4 5 ∘ current incidences. The transverse and yaw motion frequencies for 1 5 ∘ , 22 . 5 ∘ and 4 5 ∘ current incidences are higher than those for 0 ∘ current incidence. The energy levels of the yaw motion responses for 1 5 ∘ , 22 . 5 ∘ and 4 5 ∘ current incidences are about 10% of that for 0 ∘ current incidence. Moreover, parametric studies have been performed to examine the effect of submerged column height on VIM. It demonstrates that VIM in transverse direction grows significantly when submerged column height H / D is greater than 1.0. To be more specific, compared to the case with H / D = 1.44, VIM in transverse direction at H / D = 3.0 increase by around 120%.

Objectives The prevalence and dissemination of diverse NDM-producing bacteria in China was investigated. Methods We collected 1,162 isolates from 8 cities during December 2013∼May 2015 in China. The NDM-positive strains as well as the NDM genotypes in these sample were detected via Vitek 2 compact system (bioMerieux, France), 16S rRNA gene sequencing, PCR and an S1- pulsed-field gel electrophoresis assay and Southern blot hybridization. The horizontal-transfer capability of the bla NDM gene was assessed by filter mating by using a standard E.coli J53 azide-resistant strain as the recipient. Results Three genotypes (NDM-1, NDM-3 and NDM-5) of NDM-producing bacteria were identified, among which the NDM-1-positive isolates were the most frequent one. For the first time, we found NDM-5-produing S.typhimurium and NDM-3-produing E.coli in China. We also found that the NDM-positive (especially NDM-3 and NDM-5) strains were completely resistant to nearly all of the antimicrobial drugs utilized and bla NDM was mostly located on diverse plasmids with sizes ranging from 30 to 670kb. Conclusion Various species of bacteria especially the enteric pathogens with diverse NDM genotypes had spread in China. Hence, an ongoing surveillance of their dissemination is essential to prevent and control the spread of these organisms.

Food packaging, particularly active packaging, plays an important role in maintaining food quality and safety. Incorporating antimicrobial agents into films usually enhances the antimicrobial activity, but easily provokes a burst release of antimicrobials and degrades film performance. Recent studies found that addition of reinforcement agents effectively improved mechanical strength and barrier properties of packaging films. Halloysite nanotubes (HNTs) are natural clays with a unique tubular structure, possessing large surface areas and negatively charged exteriors. These properties do not only prepare HNTs as a satisfactory reinforcement agent, but also enable active agents to be loaded into the lumen or attached to the exteriors of HNTs, achieving a sustained controlled release of antimicrobials. HNTs have shown great application potential in the food industry, but currently there are no systematic reviews in this field. This review is focused on HNTs’ roles as nano-filler and nano-carrier when incorporated into food packaging systems, improving food preservation without sacrificing film performance. Effects of incorporation techniques and polymeric matrixes on film behavior were systemically reviewed, with a profound explanation on the mechanisms of carrying food preservatives. In addition, antimicrobial activities and release kinetics of HNTs based active agents were discussed in detail. Current problems and directions for the future applications of HNTs in food packaging system were analyzed in the end. In conclusion, proper use of HNTs in food packaging system is a promising way to achieving controlled release of antimicrobials, enhancing the quality and safety of fresh food during storage and transportation.

Food safety is currently a significant issue for human life and health. Various fluorescent nanomaterials have been applied in the point-of-care test (POCT) for food safety as labeling materials. However, previous fluorescent nanomaterials can cause aggregation-caused quenching (ACQ), thus reducing the detection sensitivity. Conversely, aggregation-induced emission luminogens (AIEgens) are promising candidates for POCT in the food safety field because they can enhance detection sensitivity and throughput. Mycotoxins, such as aflatoxin B1 (AFB1) and cyclopiazonic acid (CPA), are a primary threat to human life and health and a significant food safety issue, and their on-site detection from farm to table is needed. Herein, an ultrasensitive point-of-care test was developed based on TPE-Br, a blue-emissive tetraphenylethylene derivative AIEgen. Under optimal conditions, this AIEgen-based lateral-flow biosensor (ALFB) allowed for a rapid response of 8 min toward AFB1 and CPA detection, with considerable sensitivities of 0.003 and 0.01 ng/mL in peanut matrices, respectively. In peanut matrices, the recoveries were 90.3%–110.0% for both mycotoxins, with relative standard deviations (RSDs) below 6%. The ALFB was further validated via UPLC-MS/MS using spiked peanut samples. AIEgens open an avenue for on-site, ultrasensitive, high-throughput detection methods and can be extensively used in point-of-care tests in food safety.

In recent years, with the increasing demand for liquefied natural gas (LNG) worldwide, a large amount of LNG is stored, processed, and transported in ports. The port's LNG storage tanks may become a hot target for terrorist attacks because the failure or destruction of these facilities will put markets, cities, and the environment at high risk. This article presents a new risk analysis method of terrorist attacks on the port's LNG Storage tanks. The steps are as follows: (1) Identify risk factors from a multidimensional perspective. (2) Analyze the risk using the Bayesian network and event tree. (3) Evaluate and quantify the accident consequence. (4) Use knowledge graph to store risk knowledge. We verify the effectiveness of the method through case studies. The defence capabilities of the police and different prevention strategies were studied. The results show significant differences in accident consequence between different defensive and emergency response forces. We also conducted nine scenario analysis, which could provide a theoretical basis and method support for public security and urban risk management departments' security prevention decisions.

Many jobs like outdoor work and emergency rescue have to be exposed to extremely cold environments. The combined effects of the cold exposure and work intensity on human cognitive performance remain unclear. In this paper, the experiments of six Chinese young men exposed to an extremely cold environment (-10 °C) were conducted in a climatic chamber. The work intensity level was graded according to the metabolic rate corresponding to three walking speeds. Nine cognitive functions and one perceived were recorded to evaluate the subjects’ cognitive performance, including NCTB (seven items), Stroop, and RPE were measured. The increase of workload from moderate to high could lead to the acceleration of fatigue speed and the aggravation of fatigue degree 5 min earlier. Moderate work intensity is a noteworthy work level in extremely cold environment, which is an inflection point in the impact of fatigue and cognitive levels. The manual dexterity significantly increases by the workload intensity, and the high work intensity makes the hands more dexterous (29% increase). Extremely cold environment has a significant effect on short-term memory (decreased 33%). The selective attention was reduced by 16% in the extremely cold environment. With the moderate work intensity in extremely cold environment, the perceived judgment response speed would decrease. The combined effects of the extremely cold environment and the workload on the cognitive functions of psychomotor ability and attention or sensorimotor speed should be paid more attention to.

Mycotoxins usually found in agricultural products such as peanut, corn, and wheat, are a serious threat to human health and their detection requires multiplexed and sensitive analysis methods. Herein, a simultaneous determination for aflatoxin B1, B2, G1, G2, ochratoxin A, zearalanone and T-2 toxin was investigated using high performance liquid chromatography coupled with tandem mass spectrometry in a single run via a home-made multiple immunoaffinity column. Four monoclonal antibodies were produced in our lab against aflatoxins, ochratoxin A, zearalanone and T-2 toxin, respectively, then combined as a pool and bound to Sepharose-4B for affinity chromatography. Seven mycotoxins were effectively extracted from the agricultural product samples by using acetonitrile/water/acetic acid (80:19:1, v/v/v) Then, the extraction was cleanup by multiple immunoaffinity column. This method demonstrated a considerable linear range of 0.30–25, 0.12–20, 0.30–20, 0.12–20, 0.60–30, 0.30–25, and 1.2–40 μg kg −1 and lower limits of detection at 0.1, 0.04, 0.1, 0.04, 0.2, 0.1 and 0.4 μg kg −1 for AFB1, AFB2, AFG1, AFG2, OTA, ZEN and T-2, respectively, in comparison with previously reported methods, as well as excellent recoveries. The mIAC capacity for AFB1, AFB2, AFG1, AFG2, OTA, ZEN, and T-2 were 187, 181, 153, 151, 105, 130, 88 ng, respectively. It was found that all of the 7 mycotoxins were present in 90 agricultural product samples. The proposed method meets the requirements for rapid sample preparation and highly sensitive identification of multiple mycotoxins in agricultural product and food safety. This method provides a promising alternative with high throughput and high sensitivity for rapid analysis of seven mycotoxins in the monitoring of food safety.

Surface-enhanced Raman scattering (SERS) is a powerful analytic tool that can provide information of molecular structures and composition of analytes. The application of SERS for ultrasensitive detection of chemical and biological molecules has attracted particular interests in recent years. Here, a novel type of three-dimensional SERS substrate with uniform hierarchical nanoflower structures was fabricated by growing dense ZnO nanowires (ZnO NWs) on ordered vertically aligned Si nanorods (Si NRs) through a chemical hydrothermal (HT) method. After being decorated with Ag nanoparticles (Ag NPs), such branched nanostructure exhibits greatly improved SERS signals with a detection limit of Rhodamine 6 G (R6 G) down to 1 pM and an excellent uniformity (relative standard deviation lowered to about 6%). Furthermore, this SERS-active substrate is successfully applied to investigate the aggregation status of human islet amyloid polypeptides (hIAPP). The structural change of amyloid aggregates can be detected from SERS spectra at a single aggregate level, providing useful information for the prevention and treatment of protein conformation diseases. Therefore, our studies not only demonstrate a promising type of SERS substrates for highly uniform, reproducible and ultrasensitive molecular detection, but also suggest a potential method for label-free detection on conformation change of amyloid peptides in aggregation process.

We report an unusual angular dependent magnetoresistance (ADMR) in single-crystalline Co films grown on Al2O3(0 0 0 1). The Co film with a thickness of 4.4 nm shows nearly zero anisotropic magnetoresistance for arbitrary magnetization orientations, and the sign of the ADMR reverses with changing Co thickness. By systematically measuring the Co-thickness-dependent anisotropic conductance in single-crystal Co/Pt, Pt/Co, and Pt/Co/Pt, we reveal that the ADMR of the Co layer grown on the Pt underlayer is significantly different from that of the Co layer grown on Al2O3(0 0 0 1). Our results suggest that the transport properties of the Co layer as a function of Pt thickness must be considered in order to better understand the spin Hall magnetoresistance in the Co/Pt bilayer.

Cytogenomic microarray analysis (CMA) offers high resolution, genome-wide copy number information and is widely used in clinical laboratories for diagnosis of constitutional abnormalities. The Cancer Genomics Consortium (CGC) conducted a multiplatform, multicenter clinical validation project to compare the reliability and inter- and intralaboratory reproducibility of this technology for clinical oncology applications. Four specimen types were processed on three different microarray platforms-from Affymetrix, Agilent, and Illumina. Each microarray platform was employed at two independent test sites. The results were compared in a blinded manner with current standard methods, including karyotype, FISH, or morphology. Twenty-nine chronic lymphocytic leukemia blood, 34 myelodysplastic syndrome bone marrow, and 30 fresh frozen renal epithelial tumor samples were assessed by all six laboratories. Thirty formalin fixed paraffin embedded renal tumor samples were analyzed at the Affymetrix and Agilent test sites only. All study samples were initial diagnostic samples. Array data were analyzed at each participating site and were submitted to caArray for central analysis. Laboratory interpretive results were submitted to the central analysis team for comparison with the standard-of-care assays and for calculation of intraplatform reproducibility and cross-platform concordance. The results demonstrated that the three microarray platforms 1) detect clinically actionable genomic changes in cancer compatible to standard-of-care methods; 2) further define cytogenetic aberrations; 3) identify submicroscopic alterations and loss of heterozygosity (LOH); and 4) yield consistent results within and between laboratories. Based on this study, the CGC concludes that CMA is a sensitive and reliable technique for copy number and LOH assessment that may be used for clinical oncology genomic analysis.

We report the fabrication of CdS quantum dot sensitized solar cells with ZnO nanowire arrays as the photoanodes. The influences of precursor solution temperature and sensitizing cycles on the performance of CdS quantum dots sensitized ZnO nanowires solar cells were studied. Successive ionic layer adsorption and reaction (SILAR) method was applied to deposit CdS quantum dots on the surface of ZnO nanowire arrays for assembling ZnO/CdS electrodes. The results of scanning electron microscopic (SEM), X-ray diffraction (XRD) patterns and UV–vis absorption spectroscopy indicated that the ZnO nanowires electrodes were well-covered with CdS quantum dots. The temperature of the ethanol sensitizing solutions significantly influenced the performance of ZnO/CdS electrodes by affecting the rate of deposition reaction and the penetration ability of ethanol solution. The CdS quantum dots sensitized ZnO-based solar cells exhibited a short-circuit current density ( J sc ) of 3.1 mA/cm 2 , an open-circuit voltage ( V oc ) of 0.55 V and a photovoltaic conversion efficiency of 0.72%, which is much higher than that reported in literatures, under the illumination of one sun (AM 1.5, 100 mW/cm 2 ) when the temperature of the ethanol solutions was 60 °C and ZnO arrays were sensitized for seven times.

The Meihe Basin is a Paleogene pull-apart basin. Long-flame coal, lignite and oil shale are coexisting energy resources deposited in this basin. Ninety-seven samples, including oil shales, coals, brown to gray silt and mudstone, have been collected from the oil shale- and coal-bearing layers to discover the rare earth element geochemistry. The total REE contents of oil shales and coals are 137–256 μg/g and 64–152 μg/g respectively. The chondrite-normalized patterns of oil shales and coals show LREE enrichments, HREE deficits, negative Eu anomalies and negligible Ce anomalies. The chemical index of alteration (CIA) as well as some trace elements is often used to reflect the paleoenvironment at the time of deposition. The results show that fine-grained sediments in both layers were deposited in dysoxic to oxic conditions and in a warm and humid climate, and coals were deposited in a warmer and more humid climate than oil shales. Oil shales and coals are both in the early stage of diagenesis and of terrigenous origin. Besides, diagrams of some major, trace and rare earth elements show that the fine-grained sediments of both layers in the Meihe Basin are mainly from the felsic volcanic rocks and granite, and that their source rocks are mostly deposited in the continental inland arc setting. The analysis of major elements shows that Si, Al, K and Ti, in both layers, are found mainly in a mixed clay mineral assemblage and that Si is also found in quartz. Sodium occurs primarily in clay minerals, whereas Ca is found mainly in the organic matter. In the coal-bearing layer, iron is mainly controlled by organic matter rather than detrital minerals. In contrast, in the oil shale-bearing layer, neither detrital minerals nor organic matter exert a control on the iron content. Analyzing the relationship between rare earth elements and major elements shows that REEs in the oil shales and the coals are both of terrigenous origin and are mainly controlled by detrital minerals rather than by organic matter. In both layers, REEs have no relationship with fine-grained phosphates, and during the weathering process, the REEs were not very mobile and were resistant to fractionation.

Palmitoyl diglycol amide (PDGA) and its anionic derivatives, palmitoyl diglycol amide sulfate (PDGAS), palmitoyl diglycol amide carbonate (PDGAC), and nonionic derivatives, palmitoyl monoethanol amide ethoxylates (PMEA-EOn, n = 2, 3, 4), were synthesized, characterized and incorporated into surfactant formulations for reducing Daqing crude oil/connate water IFT by mixing with a lipophilic surfactant, didodecylmethylcarboxyl betaine (diC12B), and a hydrophilic surfactant, cetyldimethylcarboxyl betaine (C16B), in absence of alkali. Suffering from solubility limit PDGA can be incorporated into the formulation at a molar fraction of 0.5 and ultra low IFT can be attained in a total surfactant concentration range, 0.01–0.3 wt.%. The nonionic derivatives, PMEA-EOn (n = 2, 3, 4), with improved solubility in water, can be incorporated into the formulation at a higher molar fraction, 0.6, and ultra low IFT can be attained in a wide total surfactant concentration range, 0.05–0.5 wt.%. The increase of EO number in PMEA-EOn can be compensated by increasing/decreasing the molar fraction of diC12B/C16B in the mixture. The anionic derivatives, PDGAS and PDGAC, however, can be incorporated into the formulations at a much lower molar fraction, 0.25 and 0.29, respectively. Although the increased hydrophilicity of the anionic derivatives can be compensated by increasing the molar fraction of diC12B in the mixtures, and ultra low IFT can be achieved in the same total surfactant concentration range, the overall IFT behavior is not so good as systems containing the nonionic derivatives. It seems that the IFT behavior of these systems correlates well with the cross section area, a∞, of PDGA and its derivatives, those with smaller a∞, give in general better IFT behavior, showing that the cross section area of a surfactant at interface is crucial for selecting surfactants for surfactant–polymer flooding free of alkali.

Reflection absorption infrared spectroscopy was used to study the reaction of adsorbed molecular oxygen with carbon monoxide to produce adsorbed carbon dioxide at 130 K. By simultaneously monitoring the O–O stretch of O 2 (ads), the C–O stretch of CO(ads), and the asymmetric O–C–O stretch of CO 2 (ads), it is found that there is an O 2 –CO interaction, suggesting that the transition state involves direct transfer of an O atom from O 2 (ads) to CO, rather than through reaction of CO(ads) with a hot surface O atom produced from O 2 dissociation.

The flows around two tandem circular cylinders in the subcritical and supercritical flow regimes are studied through three-dimensional numerical simulations. Different spacing ratios L / D (where L is the center-to-center distance between the two cylinders with D being the diameter of the cylinders) from 2.0 to 5.0 is considered. The instantaneous flow structures, pressure distributions and hydrodynamic forces on two tandem cylinders are analyzed at subcritical ( R e = 2.2 × 10 4 ) and supercritical ( R e = 3.0 × 10 6 ) Reynolds numbers. The present numerical solutions demonstrated that at the two R e , for L / D 3.5 , the shear layer from the upstream cylinder reattaches on the surface of the downstream cylinder and vortex street is only formed behind the downstream cylinder, while the shear layer from the upstream cylinder rolls up alternately for L / D ≥ 3.5 , and vortex shedding occurs from both upstream and downstream cylinders. Compared with the flow characteristics at R e = 2.2 × 10 4 , for R e = 3.0 × 10 6 , the flow separation positions on the upstream cylinder move backward and the width of the wake behind the upstream cylinder becomes narrower, which leads to forward movement of the reattachment position. At the supercritical Reynolds number, the mean drag and fluctuating lift coefficients of the upstream cylinder are nearly independent of L / D while the sharp increase of force coefficients of the downstream cylinder occurs for L / D = 3.5 . Comparing to the case at the subcritical Reynolds number, higher vortex-shedding frequencies from the upstream and downstream cylinders are identified. It is also revealed that the slope of the best fit line for φ (the phase lag of the fluctuating lift force between two cylinders) and L / D increases at the supercritical Reynolds number. In addition, for L / D = 2.5 , the mean drag coefficients of the upstream cylinder decrease sharply for R e > 1.0 × 10 5 , while those of the downstream cylinder rise slightly with the growing R e . Moreover, the fluctuating lift coefficients of the upstream cylinder are almost independent of R e , but those of downstream cylinder drop as R e increases.