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This paper is devoted to the analytical study of traveling wave solutions to a generalized Boussinesq equation with nonlinear dispersion. Utilizing the bifurcation method of dynamical systems, the existence of compacton and peakon solutions are established. Under certain parameter conditions, the compacton and peakon solutions can be bifurcated by smooth periodic wave solutions, smooth solitary wave solutions, and singular cusp solutions. Numerical simulations are supplied to corroborate the analytical results. Some previous results are extended. [ABSTRACT FROM AUTHOR]

Ignition delay times (IDTs) were measured in a shock tube facility for NH 3 /n-heptane mixtures with NH 3 concentrations in the blending fuel ranging from 0.3 to 0.95 by molar fraction. The measurements were conducted under low pressure of 2 atm and intermediate temperatures of 1350–1500 K at equivalence ratios of 0.5, 1, and 2. With the increase of n-heptane content or equivalence ratio, there is a decrease in the IDTs of NH 3 /n-heptane mixtures at intermediate temperatures. A detailed mechanism was updated in this study based on the mechanism of Dong et al. Subsequently, the proposed mechanism was compared to existing blending mechanisms of ammonia and n-heptane in terms of laminar burning velocities (LBVs), IDTs, and species profiles reported in literature. The present model improved the predictions in reproducing the performed experimental measurements compared to previous mechanisms. Finally, rate of production (ROP), sensitivity analysis, and instantaneous and cumulative reaction path analysis were performed to interpret the experiment observations and deepen the understanding of auto-ignition kinetics of ammonia and n-heptane. The results indicate that intermediate species, such as C 2 H 4 and C 3 H 6 , characterized by long lifespans and high concentrations during n-heptane decomposition, play a crucial role at elevated temperatures, while the significance of n-heptane dehydrogenation by NH 2 diminishes with increasing temperature. [ABSTRACT FROM AUTHOR]

• IDTs of H 2 /NC 7 H 16 mixture were measured in RCM. • A skeletal H 2 /NC 7 H 16 oxidation mechanism was developed. • Hydrogen diffusion velocity is determined by injection direction. • Hydrogen diffusion velocity influences pre-mixture homogeneity and slipping. • Hydrogen injection timing affects pre-mixture homogeneity and slipping. Achieving efficient lean combustion with homogeneous pre-mixtures is essential in marine low-speed two-stroke hydrogen/diesel engines. However, measures enhancing pre-mixture homogeneity may lead to hydrogen slipping. To address this, the numerical simulation research on injection process was carried out. A skeletal hydrogen/n-heptane oxidation mechanism with 49 species and 174 reactions was developed and validated against experimental ignition delay times in rapid compression machine with temperature range from 600 K to 800 K and pressure of 8 bar and 24 bar. Based on the mechanism, the influence of hydrogen injection parameters on pre-mixture homogeneity and hydrogen slip was investigated by three-dimensional computational fluid dynamic simulation. The angular, radial, and longitudinal velocity of hydrogen diffusion, determined by side and downward angle of hydrogen injectors directly impact the circumferential, radial, and longitudinal homogeneity of pre-mixture. By affecting swirl intensity and friction between fluid and cylinder wall, side angle indirectly influences longitudinal velocity, which dominates hydrogen slipping. Moderate side (10° − 20°) and downward (0° − 20°) angles of hydrogen injectors ensure both pre-mixture homogeneity and prevent hydrogen slipping. Finally, the influences of injection timing on pre-mixture homogeneity and hydrogen slipping were studied. An advanced injection timing (earlier than 226°CA) enhances mixing time but increases hydrogen slip risk. Conversely, delaying injection timing (later than 238°CA) prevents slipping but reduces pre-mixture homogeneity due to shorter mixing time. [ABSTRACT FROM AUTHOR]

In order to avoid the abnormal combustion in high-power hydrogen engine, a 3D CFD numerical model of a direct-injection spark-ignition hydrogen engine was built up based on a large-bore medium-speed four-stroke marine diesel engine using CONVERGE software. To obtain the influence of injection parameters on mixture homogeneity, a dimension reduction optimization method was proposed. The results revealed that the turbulence intensity and the penetration distance varied with the injection parameters, determined the level of mixture homogeneity. The performance comparison between the hydrogen engine and prototype diesel engine showed a great potential of hydrogen in internal combustion (IC) engines. • Process of improving homogeneity can be simplified by optimizing turbulence intensity and injection penetration distance. • Turbulence intensity and injection penetration distance varied with injection system parameters. • The higher the turbulence intensity, the faster the mixing rate. • Neither too long nor too short injection penetration distance was conducive to mixing. [ABSTRACT FROM AUTHOR]

[Display omitted] • A highly selective Hg2+ sensor QPE was developed based on quinolimide. • QPE had high sensitivity, low LOD and LOQ, wide pH range, and rapid response. • QPE -loaded test strips were fabricated for the visual detection of Hg2+. • QPE had been used for tracing Hg2+ in real water and soil samples and living cells. Herein, a novel fluorescent sensor QPE based on quinolimide was developed, which displayed the highly selective response to Hg2+ through the turn-on signal in aqueous media. The corresponding recognition mechanism of QPE for Hg2+ was investigated by the titration experiments, Job's plots, HRMS, and DFT calculations analysis. QPE could detect Hg2+ in a broad pH range (pH = 4–9) with the LOD of 20 nM and the LOQ of 66 nM. Meanwhile, QPE -loaded test strips were demonstrated in the visual detection of Hg2+. Importantly, QPE exhibited the reliable capability to track Hg2+ in real water and soil samples and yeast cells, indicating that QPE could be used as a prospective tool for monitoring Hg2+ in wide fields. [ABSTRACT FROM AUTHOR]

Studies investigating the effects of inland recharge on coastal groundwater dynamics were carried out typically in unconfined aquifers, with few in confined aquifers. This study focused on the groundwater dynamics in confined aquifers with seasonally sinusoidally fluctuated inland groundwater head and constant sea level by numerical simulations. It is known that the mixing zone (MZ) of saltwater wedge in response to the seasonal oscillations of inland groundwater head swings around the steady‐state MZ. However, our simulation results indicate that even the most landward freshwater‐saltwater interface over a year is seaward from the steady‐state location when the hydraulic conductivity K is ≤10−4 m/s under certain boundary conditions with given parameter values. That is, seasonal oscillations of inland groundwater head may reduce seawater intrusion in confined coastal aquifers when K ≤ 10−4 m/s. Sensitivity analysis indicates that for aquifers of K ≤ 10−4 m/s, the larger the inland head fluctuation amplitude is, the less the seawater intrudes. This is probably due to the reason that the seawater intrusion time decreases with the increase of fluctuation amplitude when K ≤ 10−4 m/s. Numerical simulations demonstrate that seasonal inland groundwater head oscillations promote the annual averaged recirculated seawater discharge across the seaward boundary. Article impact statement: Seasonally oscillated inland water level may prevent seawater intrusion in confined aquifers when K ≤ 10−4 m/s under certain conditions. [ABSTRACT FROM AUTHOR]

The cationic dimethyldioctadecylammonium/trehalose 6,6,9-dibehenate (DDA/TDB) liposome is as a strong adjuvant system for vaccines, with remarkable immunostimulatory activity. The mucosal administration of vaccines is a potential strategy for inducing earlier and stronger mucosal immune responses to infectious diseases. In this study, we assessed whether the intranasal administration of cationic DDA/TDB liposomes combined with influenza antigen A (H3N2) can be used as a highly efficacious vaccine to induce mucosal and systemic antibody responses. Confocal laser scanning microscopy and a flow-cytometric analysis showed that the uptake of the cationic DDA/TDB liposome carrier was significantly higher than that of neutral 1,2-distearoyl-sn-glycero-3-phosphocholine/cholesterol (DSPC/Chol) or cationic 1,2-dioleoyl-3-trimethylammonium-propane/3β-(N-[N′,N′-dimethylaminoethane]-carbamoyl (DOTAP/DC-Chol) liposomes. Our results indicate that the cationic DDA/TDB liposome is more effective in facilitating its uptake by dendritic cells (DCs) in vitro than the DSPC/Chol or DOTAP/DC-Chol liposome. DCs treated with DDA/TDB liposomes strongly expressed CD80, CD86, and MHC II molecules, whereas those treated with DSPC/Chol or DOTAP/DC-Chol liposomes did not. C57BL/6 mice intranasally immunized with H3N2-encapsulating cationic DDA/TDB liposomes had significantly higher H3N2-specific s-IgA levels in their nasal wash fluid than those treated with other formulations. The DDA/TDB liposomes also simultaneously enhanced the serum IgG IgG2a, IgG1, and IgG2b antibody responses. In summary, DDA/TDB liposomes effectively facilitated their uptake by DCs and DCs maturation in vitro, and induced significantly higher mucosal IgA, systemic IgG, IgG1, and IgG2b antibody titres than other formulations after their intranasal administration in vivo. These results indicate that DDA/TDB liposomes are a promising antigen delivery carrier for clinical antiviral applications. [ABSTRACT FROM AUTHOR]

Multicomponent formulations have attracted increasing attention because of their favourable patient compliance and greater therapeutic effect. The aim of this study was to develop a multicomponent nanosuspension formulation of bufadienolides, the antitumor components of a traditional Chinese medicine, toad venom, using a wet-milling technique to improve its dissolution behaviour. Croscarmellose sodium (CCS) and sodium lauryl sulfate (SLS) were chosen as the combined stabilizers of the nanosuspension. A Taguchi orthogonal array design was used for this study to optimize the formulation and process parameters. The optimized nanosuspension was characterized by its particle size distribution, zeta potential, morphology, crystallinity, molecular interactions, stability and dissolution. The results showed that the nanosuspension was a homogeneous amorphous system with average particle sizes of <100 nm and significantly improved dissolution behaviour. It was also physically stable for at least 2 months; steric and kinetic stabilization were its main stability mechanisms. These findings suggested that the use of wet milling to fabricate nanosuspensions is a promising method for achieving the fast and synchronized dissolution of multicomponent formulations, presumably increasing the bioavailability of poorly water-soluble drugs. [ABSTRACT FROM AUTHOR]

The cationic dimethyldioctadecylammonium/trehalose 6,6,9-dibehenate (DDA/TDB) liposome is as a strong adjuvant system for vaccines, with remarkable immunostimulatory activity. The mucosal administration of vaccines is a potential strategy for inducing earlier and stronger mucosal immune responses to infectious diseases. In this study, we assessed whether the intranasal administration of cationic DDA/TDB liposomes combined with influenza antigen A (H3N2) can be used as a highly efficacious vaccine to induce mucosal and systemic antibody responses. Confocal laser scanning microscopy and a flow-cytometric analysis showed that the uptake of the cationic DDA/TDB liposome carrier was significantly higher than that of neutral 1,2-distearoyl-sn-glycero-3-phosphocholine/cholesterol (DSPC/Chol) or cationic 1,2-dioleoyl-3-trimethylammonium-propane/3β-(N-[N′,N′-dimethylaminoethane]-carbamoyl (DOTAP/DC-Chol) liposomes. Our results indicate that the cationic DDA/TDB liposome is more effective in facilitating its uptake by dendritic cells (DCs) in vitro than the DSPC/Chol or DOTAP/DC-Chol liposome. DCs treated with DDA/TDB liposomes strongly expressed CD80, CD86, and MHC II molecules, whereas those treated with DSPC/Chol or DOTAP/DC-Chol liposomes did not. C57BL/6 mice intranasally immunized with H3N2-encapsulating cationic DDA/TDB liposomes had significantly higher H3N2-specific s-IgA levels in their nasal wash fluid than those treated with other formulations. The DDA/TDB liposomes also simultaneously enhanced the serum IgG IgG2a, IgG1, and IgG2b antibody responses. In summary, DDA/TDB liposomes effectively facilitated their uptake by DCs and DCs maturation in vitro, and induced significantly higher mucosal IgA, systemic IgG, IgG1, and IgG2b antibody titres than other formulations after their intranasal administration in vivo. These results indicate that DDA/TDB liposomes are a promising antigen delivery carrier for clinical antiviral applications. [ABSTRACT FROM AUTHOR]

In Jiaozhou Bay, there are four wetland types, including sandy beaches, mud flats, tidal marshes, and estuarine intertidal zones. Four typical transects representing each of the wetland types were selected to investigate the flow dynamics, seawater-groundwater exchange and nutrients carried by submarine groundwater discharge (SGD). Based on field measurements of groundwater heads and salinity along each transect, the SGD averaged over the observation period was estimated using generalized Darcy's law. The SGD along the four transects ranges from 3.6 × 10 −3 to 7.6 cm/d with the maximum occurring at the sandy beach. The SGD rate has a good correlation with the hydraulic conductivities of the wetland sediments. There is a positive correlation between the ratio of NO 3 -N/DIN and SGD rates. The SGD-associated nutrient output rate ranges from 3.3 × 10 −2 to 9.5 mmol/m 2 /d for DIN (dissolved inorganic nitrogen), and from 6.2 × 10 −5 to 1.8 × 10 −2 mmol/m 2 /d for DIP (dissolved inorganic phosphorus). Compared to the nutrients delivered by the river, nutrients carried by SGD provide a more important source for the phosphate-limited environment to plankton in Jiaozhou Bay. [ABSTRACT FROM AUTHOR]

Luminescent semiconductor nanocrystals, also known as quantum dots (QDs), have rich surface chemistry and unique optical properties that make them useful as probes or carriers for molecular diagnostics and therapeutics. However, their potential toxicity and instability in biological environments have puzzled scientific researchers. Much research effort has been devoted to encapsulation of QDs with liposomal hybrids to make them versatile nanocarriers for simultaneous therapeutics and diagnostics (theranostics) and considerable progress has been made over recent years. We provide an overview of the use of QD–liposome complexes (QLCs) for imaging applications, in particular applications in theranostics. More specifically, the design considerations, intracellular uptake and tissue-specific targeting of QLCs are highlighted. Current findings of QLCs for theranostics are discussed. We also discuss the challenges and highlight future directions for applications of liposome–QD hybrid nanocarriers in the biomedical arena. [ABSTRACT FROM AUTHOR]

• Ignition properties of H 2 /n-C 7 H 16 mixture was revealed by shock tube and mechanism. • H 2 /n-C 7 H 16 mixtures with more hydrogen and lower equivalence ratio have shorter IDT. • More active n-C 7 H 16 consumes before H 2 and triggers later radicals' reactions. • A skeletal hydrogen/PRF mechanism was proposed based on a skeletal PRF mechanism. In the present work, the experiments of measuring ignition delay times (IDTs) of the hydrogen/ n -heptane mixture at high temperature (1130–1485 K) and low pressure (1.25 atm) by a shock tube is implemented. The results show that mixtures with higher hydrogen proportion and lower equivalence ratio present shorter IDT. In the case of high hydrogen proportion, the n -heptane addition causes an obvious inhibition effect on the ignition of the mixture. Whereas, as the hydrogen proportion decreases, such inhibition effect weakens. As the experimental values are consistent with the predicted IDTs by NUI (National University of Ireland) mechanism, the NUI mechanism was selected to conduct the kinetic study. The consumption of n -heptane at the initial stage of reaction is earlier than that of hydrogen because the activities of n -heptane's H-abstraction and decomposition reactions are relatively high. With shock tube experimental data as the calibration basis, a skeletal hydrogen/PRF (Primary Reference Fuel) mechanism, was updated from a skeletal PRF mechanism. The skeletal hydrogen/PRF mechanism, consisting of 49 species and 162 reactions had been validated against shock tube experiment of hydrogen, n -heptane, isooctane pure fuel, PRF, and hydrogen/ n -heptane mixture. [ABSTRACT FROM AUTHOR]

A novel sensor T2 was synthesized through the introduction of N,N -di (pyridin-2-ylmethyl)ethane-1,2-diamine into the quinolimide fluorophore. T2 could detect Cd2+ and Zn2+ via fluorescence enhanced signals, and Cd2+ was distinguished from Zn2+ through the visible color change and the addition of S2−. The T2 -Cd2+ complex exhibited the exceptional selectivity to S2− through the restored fluorescence. Moreover, the combinational logic gate with OR and INHIBIT functions was constructed by using the controlled fluorescence "off-on" states of T2. The recoveries of Cd2+ and Zn2+ in water samples with T2 were in range of 95.6%–106.5%. And T2 was used for the visualization of Cd2+, Zn2+, and S2− in yeast cells. [Display omitted] • The quinolimide-based sensor T2 was developed for sensing Cd2+, Zn2+, and S2−. • T2 could distinguish Cd2+ from Zn2+ through the visible color change and the addition of S2−. • The T2-Cd2+ complex exhibited the exceptional selectivity to S2−. • The combinational logic gate with OR and INHIBIT functions was constructed. • T2 was applied to detect Cd2+, Zn2+, and S2− in water samples as well as in yeast cells. [ABSTRACT FROM AUTHOR]

Steady-state seawater–groundwater interactions are simulated for homogeneous, anisotropic unconfined coastal aquifers using the two-dimensional numerical model MARUN. The spatial salinity distributions are approximately independent of the horizontal hydraulic conductivity K x when α L K x K z ⩾ 10 −6 m 2 /s. Here K z is vertical hydraulic conductivity and α L is longitudinal dispersivity. Both the fresh groundwater discharge rate Q f and seawater recirculation rate Q s depend linearly on K x . These conclusions are validated by a semi-analytical method. The increase of anisotropy ratio pushes the saltwater wedge interface seaward and reduces Q s . The increment of the longitudinal/transverse dispersivity ratio with fixed longitudinal dispersivity decreases the slope of isosalines and Q s . When the seabed slope angle θ increases from 0.01 to π /2, the freshwater–seawater interface moves landward. The increment of θ increases Q s slightly when θ < π /4 and reduces Q s when θ > π /4. The inland recharge rate Q f is independent of the seabed slope. [ABSTRACT FROM AUTHOR]

Knee osteoarthritis (KOA) is an increasingly prevalent heterogeneous disease characterized by cartilage erosion and inflammation. As the main chemical constituent of Angelicae Pubescentis Radix (APR), an anti-inflammatory herbal medicine, the potential biological effects and underlying mechanism of osthole on chondrocytes and KOA progression remain elusive. In this study, the potential effect and mechanism of osthole on KOA were investigated in vitro and in vivo. We found that osthole inhibited IL-1β-induced apoptosis and cartilage matrix degeneration by activating autophagy in rat chondrocytes. In addition, osthole could activate autophagy through phosphorylation of AMPK/ULK1, and AMPK serves as a positive upstream regulator of ULK1. Furthermore, KOA rats treated with osthole showed phosphorylation of the AMPK/ULK1 pathway and autophagy activation, as well as cartilage protection. Collectively, the AMPK/ULK1 signaling pathway can be activated by osthole to enhance autophagy, thereby suppressing KOA development. Osthole may be a novel and effective therapeutic agent for the clinical treatment of KOA. [ABSTRACT FROM AUTHOR]

[Display omitted] A new quinolimide derivative MSH was designed and developed as a highly sensitive Zn2+ fluorescent turn-on sensor in neutral aqueous media. After binding Zn2+ with a 2:1 stoichiometry, the excellent fluorescence enhancement (Φ Zn(II) = 0.555) of MSH was observed, along with the low LOD of 8 nM, wide pH usage range (pH = 4–12), and fast response time of less than 15 s. The combinational logic gate and the memory device were constructed to take advantage of the emission of MSH controlled by Zn2+ and EDTA. Additionally, Zn2+ in actual water samples was detected with the satisfactory recovery rates between 96.6 % and 104 %. And MSH was successfully fabricated into paper strips and used as an imaging tool in yeast cells for tracking Zn2+ levels. [ABSTRACT FROM AUTHOR]

The analysis of gene expression data using existing methods and tools has become a fundamental approach for researchers to explore the mechanisms of hypertension. However, many researchers lack programming skills or statistical knowledge. Although gene expression data is widely available, they originate from various experiments with different standards and quality levels, causing inconvenience to researchers. While tools and databases with interactive interfaces exist for data analysis, they may have limited applicability. This study aimed to construct High Blood Pressure Gene Expression Omnibus (HBPGEO), a program based on the R Shiny platform. It integrated the discovery of differentially expressed genes, hub gene identification, gene function analysis, and more. It allowed users to select suitable methods and set different parameters during analysis, visualize results interactively, and download the analyzed results. The study successfully utilized HBPGEO to identify hypertension-related biomarkers. [ABSTRACT FROM AUTHOR]

Background: Osteoporosis (OP) is a metabolic disease that involves microstructure destruction and fracture damage. The present study probed into the significance of miR-215-5p in OP progression.Methods: Serum samples were collected from surgical patients and healthy controls. qRT-PCR analysis was utilized to determine the miR-215-5p level in clinical samples and human bone mesenchymal stem cells (hBMSCs) induced by β-glycerol phosphate. A dual luciferase reporter assay was exploited to examine the targeted relationship between miR-215-5p and XIAP. The mineralization and calcium deposition of hBMSCs were assessed by detection of ALP activity, Alizarin red staining, and osteoblast marker expression. Protein expression was determined by western blot analysis.Results: MiR-215-5p was significantly reduced in patients with OP and increased in hBMSCs treated with β-glycerophosphate. Enhanced miR-215-5p level triggered augment in osteoblast markers (Alkaline phosphatase/ ALP, Osteocalcin/ OCN, and Runt-Related Transcription Factor 2/ Runx2), which was accompanied by the increase of ALP activity in hBMSCs and accumulation of Calcium. Functional experiments show that XIAP was a target of miR-215-5p and negatively modulated by miR-215-5p. XIAP expression levels were increased in OP samples, and decreased XIAP in β-glycerophosphate-treated hBMSCs inhibited its' osteogenic differentiation. Functional loss and acquisition experiments depicted that miR-215-5p promoted the differentiation of hBMSCs by inhibiting the XIAP level, playing a protective role in the pathogenesis of OP.Conclusions: β-glycerophosphate promoted the osteogenic differentiation of hBMSCs, increased miR-215-5p level, and decreased XIAP. miR-215-5p stimulated osteogenic differentiation of hBMSCs by targeting XIAP, shedding new insights for the detection and therapy of OP. [ABSTRACT FROM AUTHOR]

• Auto-ignition properties of ammonia with low n-heptane content were studied using RCM. • The IDTs were measured in the temperature range 620–970 K and pressure range 15–25 bar. • An optimization was conducted based on the existing detailed reaction mechanism. • A small content of n-heptane has a great effect on the IDT and HRR of the mixture. • N-heptane is consumed mainly by the reaction of extracting H atoms by NH2. The low reactivity of ammonia leads to a low combustion efficiency of premixed combustion mode ammonia-diesel engines. In order to overcome this shortcoming, a small amount of diesel is pre-injected into the ammonia pre-mixture to increase the reactivity. Therefore, this study investigated the auto-ignition characteristics of lean-equivalent-rich ammonia/n-heptane mixtures at low n-heptane blending ratios (2 %&5 %&10 %) and wide thermodynamic conditions (Temperature range of 620–970 K, Pressure range of 15–25 bar) via rapid compression machine. The results showed that a small content of n-heptane had a strong ignition-promoting effect: significantly reducing the Ignition Delay Times (IDTs) and increasing the heat release rate. Besides, the IDTs of the mixture decreased with the increase in equivalence ratio, while the stoichiometric mixture showed the highest heat release rate. Moreover, an improved dual-fuel mechanism, which dramatically enhanced the predictive performance of IDTs for ammonia/n-heptane and pure ammonia mixtures, was proposed to illuminate the reaction kinetic properties. N-heptane is consumed prior to ammonia and at a higher rate. The reaction of NH 2 extracting H atoms from n-heptane was the main consumption reaction of n-heptane at low n-heptane content conditions. And the reaction of ammonia consuming OH radicals was the most ignition-inhibiting reaction. Besides, the reaction NH 3 + O 2 = NH 2 + HO 2 plays an important role in the extent of the negative temperature coefficient effect for the mixture under different blending ratios and equivalence ratios. [ABSTRACT FROM AUTHOR]

Abstract: Model calculations for the n+56Fe reaction have been performed by using extended UNF code, which is based on the unified Hauser–Feshbach and exciton model. Based on the excellent agreement with the experimental double-differential cross-sections of neutron, alpha and proton, the total kerma coefficients are derived naturally with the formula (), which contains more comprehensive parameter information. The discrepancies of total kerma coefficients between the experimental data, evaluated data and the calculated results of this paper have been further analyzed, and one can have some confidence in predicting the kerma coefficients derived naturally by this model calculation. [ABSTRACT FROM AUTHOR]

The development of methanol/diesel dual-fuel engines urgently requires further study on chemical kinetic models for binary fuels. Ignition delay of lean and stoichiometric methanol/n-heptane mixtures (30/70, 50/50, 70/30, and 90/10) diluted with argon was investigated at high temperature (T = 1195 K–1514 K) and low pressure (p = 2 bar) using an aerosol shock tube and a detailed LLNL3.1 mechanism. The results indicated that LLNL3.1 mechanism agreed well with the current measurements. An increase in methanol can accelerate the ignition process at Ф = 1, because of the key radical---HO2, produced by CH2OH + O2=CH2O + HO2, which was affected by the methanol concentration. HO2 would subsequently attack the parent fuels and combine with H radical (HO2+H = 2OH), leading to the booming radical pool. For lean mixtures, n-heptane promoted the reactivity of system due to its high sensitivity to reaction H + O2=O + OH. The higher initial O2 concentration expedited this reaction and shortened the IDT. Besides, both methanol and n-heptane undergo H-abstraction reaction mostly by H radical, however, these reactions showed an inhibition effect on reactivity. This is caused by the competition for H radical between O2 and the parent fuels. Also, the fuel radicals, produced by C7H15-3, had a low decomposition reaction rate thus slowing down the chain branching and suppressing the reactivity of system. • Ignition characteristics of methanol/n-heptane mixtures were studied by shock tube and mechanism. • Methanol accelerated the auto-ignition for stoichiometric mixtures due to the HO2 radical. • N-heptane promoted the reactivity for lean mixtures due to its high O2 sensitivity. • H-abstraction of the parent fuels by H radical showed an inhibition on auto-ignition. [ABSTRACT FROM AUTHOR]

• Influence of exhaust gases on the ignition of CH 4 /n-C 7 H 16 mixture were revealed. • Thermal, chemical and third-body collision effects are qualitatively compared. • CO 2 suppressed ignition due to its thermal and chemical effect. • H 2 O accelerated ignition due to its third-body and chemical effect. • The addition of CO 2 /H 2 O mixture slightly fastened auto-ignition of CH 4 /n-C 7 H 16. To further optimize the combustion performance of natural-gas/diesel engine under exhaust gas recirculation (EGR) condition, influence of physicochemical impacts of H 2 O and CO 2 on the ignition characteristics of n-heptane/methane mixture (Φ = 0.5/1.0) under various thermodynamic conditions (p = 2 bar/1199 K < T < 1568 K, p = 60 bar/700 K < T < 1200 K) were investigated by shock tube and NUI mechanism. Experiments indicated at p = 2 bar/1199 K < T < 1568 K, CO 2 and H 2 O additions increased and shortened ignition delay times (IDT) respectively. Mixture of CO 2 and H 2 O slightly accelerated ignition. Original and minor modified NUI mechanism well captured the inhibition and acceleration effect of CO 2 and H 2 O on ignition respectively. Both thermal and chemical effects of CO 2 (R36:CO + OH = CO2 + H) were responsible for its ignition inhibition impacts at higher temperatures. Whereas thermal effect of CO 2 became the dominant factor at lower temperatures. Chemical effect of H 2 O (H 2 + OH<=>H + H 2 O&O + H 2 O<=>2OH) promoted OH formation and enhanced whole system reactivity, which suppressed its thermal effect and accelerated ignition process. At p = 60 bar/700 K < T < 1200 K, CO 2 addition significantly retarded ignition due to its thermal effect. At 900 K < T < 1200 K, the higher third-body efficiency of H 2 O promoted ignition (R21:H 2 O 2 (+M) = 2OH(+M)&R34:H + O 2 (+M) = HO 2 (+M)). At 700 K < T < 900 K, thermal effect of H 2 O, which suppressed its third-body effect, inhibited ignition progress. These observations implied that the impact of exhaust gases on the ignition of n-heptane/methane depended on the coupled influence mechanisms of physicochemical effects, the composition of exhaust gases and located thermodynamic conditions. At intermediate-temperature high-pressure conditions (typical thermodynamic conditions of dual-fuel engine), raising the concentration of H 2 O or CO 2 in exhaust gases accelerated or delayed the combustion progress of natural-gas/diesel engine at EGR condition by enhanced third-body effect or thermal effect respectively. [ABSTRACT FROM AUTHOR]

The natural radioisotope radon (222Rn) has been widely used as a tracer for quantifying submarine groundwater discharge (SGD). Applicable equipment for continuous radon-in-water detection using a radon-in-air monitor includes the "RAD AQUA" and the "Water Probe" (both Durridge Inc., USA). Although both devices have been applied to measure 222Rn concentrations in coastal water over time periods from hours to days, the monitoring results for the same water body may differ due to the different physical driving forces for 222Rn degassing from the water, which will result in an inaccurate SGD estimate. Here the two approaches were simultaneously applied for monitoring 222Rn concentrations at the same site in the same surface-water body (Daya Bay, China). The SGD fluxes resulting from both approaches were evaluated and compared, based on the obtained time series and a 222Rn mass balance model. The results demonstrate that the average 222Rn concentration measured by the Water Probe is only ~30% of that detected by means of the RAD AQUA. The mean SGD flux estimated based on 222Rn time series measured with the Water Probe is 69% of that detected by means of the RAD AQUA. The findings of this study suggest that the RAD AQUA can capture more accurately the signals of variation of radon concentration, and is a better approach for continuously monitoring radon and quantifying SGD in coastal zones. Thus, previous studies based on 222Rn data from the Water Probe for estimating SGD and the associated nutrient flux may need re-evaluation. [ABSTRACT FROM AUTHOR]

[Display omitted] • A simple FA sensor H2 was developed based on quinolimide for the first time. • H2 had highly selective and sensitive to FA by the pseudo -first-order reaction. • H2 -loaded test strips were fabricated for the visual detection of FA. • H2 had been successfully applied to detect FA in living cells. A simple fluorescent sensor H2 containing quinolimide as a fluorophore and hydrazine as a reaction site was designed and synthesized for the detection of formaldehyde (FA). H2 had the high selectivity and sensitivity to FA through the pseudo -first-order reaction (k = 0.048 min−1), exhibiting the significantly enhanced fluorescence signal. The quantitative determination range of H2 for FA was 0–180 μM, and the LOD of FA is 1.7 μM. Moreover, H2 -loaded test strips were demonstrated in the visualization of sensing FA. And H2 was successfully applied for imaging FA in living cells. [ABSTRACT FROM AUTHOR]

Naturally occurring radon ( 222 Rn) and radium isotopes are widely used to trace water mixing and submarine groundwater discharge (SGD) in the coastal zones. However, their activities in groundwater are variable both spatially and temporally. Here, time series sampling of 222 Rn and radium was conducted to investigate their behavior in intertidal groundwater of Laizhou Bay, China. The result shows that groundwater redox conditions have an important impact on the behavior of tracers. The activities of tracers will decrease under oxidizing conditions and increase under reducing conditions. Radon and radium mass balance models were used to evaluate the flushing time and SGD based on spatial surveys in Laizhou Bay. The flushing time is estimated to be 32.9–55.3 d with coupled models, which agrees well with the result of tidal prism model. The trace-derived SGD in the whole bay ranges from 6.1 × 10 8 to 9.0 × 10 8  m 3 /d and the re-circulated seawater (RSGD) ranges from 5.5 × 10 8 to 8.5 × 10 8  m 3 /d. The average SGD and RSGD fluxes are 22.8 and 21.1 times greater than the Yellow River discharge in April 2014, respectively. The study provides a better understanding of the dynamics of coastal groundwater and behavior of tracers in a well-studied bay system. [ABSTRACT FROM AUTHOR]

Based on field measurements from two typical intertidal transects at Dan’ao Estuary, groundwater-surface water and associated nutrient exchanges are quantified. Both groundwater discharge rate (39.1 ± 7.0 cm d −1 ) and surface water inflow rate (7.7 ± 1.4 cm d −1 ) at the upstream mangrove swamp transect are much higher than those (1.6 ± 0.3 and 2.1 ± 0.4 cm d −1 , respectively) at the downstream bare flat one. This large difference leads to their contrasting nitrogen forms. Much higher water exchange rates at the upstream transect generate much higher net dissolved inorganic nitrogen (DIN, including NH 4 + , NO 2 - , and NO 3 - ), dissolved inorganic phosphorus (DIP), and dissolved silicate (DSi) fluxes (− 160.3 ± 39.2, − 14.6 ± 2.7, − 38.6 ± 7.0 mmol m −2 d −1 , respectively) than those (2.9 ± 0.9, − 0.08 ± 0.03, 1.1 ± 0.4 mmol m −2 d −1 , respectively) at the downstream one. The mangrove swamp at the upstream transect discharges substantial groundwater and associated nutrients to the estuary. The net nutrient loads by water exchange in this estuary can reach 23.5–78.7% of those by local river discharge. [ABSTRACT FROM AUTHOR]

• A quinolimide-based reversible sensor QPC for Cu2+ and S2− was developed. • QPC and its Cu2+ complex had the high specificity to detect Cu2+ and S2−. • QPC possessed high quantum yield, short response time, and low cytotoxicity. • The INHIBIT logic gate was simulated by the addition of Cu2+ and S2−. • QPC had been applied to detect Cu2+ and S2− in water samples and living cells. A quinolimide-based reversible fluorescent sensor QPC with carboxamidoquinoline as the receptor was prepared for the relay recognition of Cu2+ and S2−. QPC displayed the high selectivity and anti-interference ability to Cu2+ through the 1:1 binding mode. Subsequently, the selectively sensing S2− with the QPC Cu2+ complex gave a remarkable recovery of the emission. The LODs of QPC and its Cu2+ complex for Cu2+ and S2− were calculated to be 47.8 nM and 0.178 µM, respectively. Moreover, QPC and its Cu2+ complex had the satisfactory recoveries 93.5–105.8% for Cu2+ and 97.7–104.0% for S2− in water samples, and exhibited low cytotoxicity, which enabled them to image Cu2+ and S2− in yeast cells. [Display omitted] [ABSTRACT FROM AUTHOR]

A novel quinolimide derivative (BNAL), bearing the amide-DPA receptor at position 9 of the heterocyclic ring, was synthesized for sequential detection of Cd2+ and S2−. BNAL could discriminate Cd2+ from Zn2+, showing the turn-on response upon interaction with Cd2+. After adding S2−, the fluorescence of the BNAL -Cd2+ solution was reverted through the displacement strategy. The limits of detection (LODs) of BNAL for Cd2+ and the BNAL -Cd2+ complex for S2− were found to be 17.9 nM and 1.51 μM, respectively. Finally, cell imaging experiments showed BNAL could be successfully employed for sequentially imaging Cd2+ and S2− via the off-on-off behavior in yeast cells. [Display omitted] [ABSTRACT FROM AUTHOR]

The short-lived Ra isotope was measured in coastal water samples from Laizhou Bay, China using a radium delayed coincidence counting system. Based on the horizontal distribution of Ra and a mixing model, the horizontal eddy diffusion coefficient was estimated to be 253.1 × 10 and 56.5 × 10 m/d for the surface and middle layers, respectively. The submarine groundwater discharge (SGD) into the bay was estimated on the basis of the Ra mass balance model. The estimate of the SGD into the bay is 4.2 × 10 m/d, approximately six times the annual average flux of the Yellow River. [ABSTRACT FROM AUTHOR]

Hou, L. J.; Li, H. L.; Zheng, C. M.; Ma, Q.; Wang, C. Y.; Wang, X. J., and Qu, W. J., 2016. Seawater-groundwater exchange in a silty tidal flat in the south coast of Laizhou Bay, China. There were few studies about seawater-groundwater exchange in silty, low-permeability tidal flats with very gentle slopes. This paper reports the monitoring data and preliminary analytical results on a typical transect in a silty tidal flat with large-scale seepage faces at the south coast of Laizhou Bay, China. The 'pair-wells method', which was an improvement of the single-well method used by Ma et al. (2015) was used to estimate the seawater-groundwater exchange rate. We selected 14 locations along a typical transect in the intertidal zone, with a slope of 0.4‰ and cross-shore length of 3514 m, to install pair-wells for monitoring the groundwater head, salinity and temperature at two different depths simultaneously once per hour from 20:00 August 10th to 23:00 September 12th, 2014. The vertical hydraulic conductivity measured in situ ranges from 5.4 ×10−7 to 1.1×10−5 m s−1. The salinity of the underground brine ranges from 25 to 56 g l−1. Based on the observed data and the generalized Darcy's law, the submarine groundwater discharge (SGD) and inflow along the entire transect were estimated to be 164.0 and 6.5 m2 d−1, respectively. It is found that 80.4% of the total SGD occurred between W7 and W10, where the hydraulic conductivity is one or two orders of magnitude greater than that at other wells; and 64.6% of the total inflow occurred between W2 and W4. The single-well method, on the other hand, yields a SGD value of 223.0 m2 d−1 and inflow value of 13.3 m2 d−1. Neglecting the density effect may lead to an overestimation of the SGD by 25.6% and underestimation of the inflow by 27.4%. [ABSTRACT FROM AUTHOR]

A supported roll cutting type anti-blocking mechanism for no-till planters was designed to cut corn residues (stalks and stubble) during operation of the no-till planter in the stubble mulch field. The mechanism is equipped with both active and passive horizontal rotating parts, which can cut residues more effectively. The active horizontal rotating parts are used for cutting residues; the passive ones are used for supporting the residues left on the surface, making them always lie between the active horizontal rotating and passive horizontal rotating parts, thus preventing them from being thrown out by the cutting blade during cutting operations. The anti-blocking mechanism cuts the residues in a supported way, just like a pair of scissors, reducing power consumption during operation. The anti-blocking mechanism, which works in a passive way, is placed in front of the opener and has a combined blades structure. Eight slide-cutting blades are fixed on a blade disc and the adjacent blades are mounted on each side of the disc respectively. When it works, the blade disc travels along with the tractor and rotates about the blade shaft under the action of the soil resistance. The side-cutting blade only cuts off the stalk in a slide cutting way without crushing, thus both the rotational speed and power consumption of the blade can be reduced. Stalks can be cut off effectively when the tillage depth is not more than 60 mm through an optimal design of the curve of the side cutting edge of the slide-cutting blade. Field tests were conducted to determine the optimal operational parameters, and the rotary quadratic combination design was carried out for the active rotating blade and passive rotating blade respectively. The regression equations showing the relationship between both factors and indexes were obtained by using the Design-Expert software. Straw cutting rate increased with the increase of the radius of the passive cutting blade, and the trend of rising and gradually slowing down; Single passive cutting blade power consumption increased with the increase of the radius of the passive cutting blade, and the trend of rising gradually increases; Straw cutting rate increased with the increase of the working depth, and the trend of rising and gradually slowing down; Single passive cutting blade power consumption increased with the increase of the working depth, and the trend of the rising was gradually enhanced. Straw and stubble root cutting rate increased with the increase of the radius of the active cutting blade, and the trend of rising and gradually slowing down; Single active cutting blade power consumption increased with the increase of the radius of the active cutting blade, and the trend of rising gradually increases; Straw and stubble root cutting rate increased with the increase of the active horizontal cutter blade rotation speed, and the trend of rising and gradually slowing down; Single active cutting blade power consumption increased with the increase of the active horizontal cutter blade rotation speed, and the trend of rising gradually enhanced. The results showed the best parameter combination: the rotation speed of 120 r/min and a turning radius of 240 mm for the active rotating blade; the turning radius of 185 mm and a working depth of 95 mm for the passive rotating blade. Verification tests indicated that the corn stalk and stubble cut-off rate was 91.3% and the power consumption of a single blade was 145.2 W. This study can provide a reference for the design of no-till planters. [ABSTRACT FROM AUTHOR]

Ignition characteristics of n -hexadecane/methane mixture under low-pressure high-temperature (P : 2.0 bar, 5.0 bar & T : 1269–1887K) and high-pressure low-temperature (P : 40–140 bar & T : 700–1200 K) conditions were studied by aerosol shock tube and CHEMKIN with LLNL C16 mechanism. The results indicated that at low-pressure high-temperature conditions, increasing initial pressure and decreasing equivalence ratio could reduce ignition delay times (IDT) by 39% and 52% respectively. N-hexadecane's addition and n -hexadecane's replacement also shortened IDT by 88% and 96% separately. Raising n -hexadecane's replacement further reduced IDT. The reduction degree of IDT dramatically decreased when n -hexadecane's content was high. N-hexadecane was fully consumed earlier than methane. Radicals that formed from n -hexadecane's decomposition induced H-abstraction of n -hexadecane, which advanced methane's slow oxidation. H was the crucial radical in n -hexadecane's H-abstraction reactions. At ultra-high-pressure low-temperature condition, adding n -hexadecane and increasing n -hexadecane content dramatically reduced IDT. With n -hexadecane's H-abstraction dominating ignition process, n -hexadecane's decomposition was significantly inhibited at low-temperature condition. OH was the key radical in n -hexadecane's H-abstraction reactions. The obviously suppressed n -hexadecane's decomposition was responsible for the same end time point of complete consumption of two fuels. These results are helpful for providing control methods for natural-gas preignition and abnormal combustion triggered by lubricating oil in dual-fuel marine engine. • Ignition characteristics of n -hexadecane/methane mixture was investigated by aerosol shock tube and kinetic study. •The addition of n -hexadecane obviously shortened ignition delay times of methane mixture. •The replacement of methane with n -hexadecane further shortened ignition delay times. •At low-pressure high-temperature, time point of complete n -hexadecane consumption was earlier than that of methane. •At high-pressure low-temperature, time point of complete n -hexadecane consumption was the same as methane. [ABSTRACT FROM AUTHOR]

To acquire ignition control methods for dual-fuel marine engine and HCCI engine, ignition characteristics of lean n-heptane/methane mixture under pressure of 2.0 bar and temperature range from 1241 to 1825 K were studied by shock tube and CHEMKIN with LLNL3.1 mechanism. And ignition processes under temperature range from 700 to 1200 K and pressure range from 40 to 140 bar were investigated by CHEMKIN with NUI mechanism. The results illuminate that at low-pressure high-temperature condition, n-heptane's replacement and the increase of n-heptane content obviously reduced ignition delay times (IDT). The reduction degree of IDT decreased when n-heptane content was high. N-heptane's addition also reduced IDT. But this reduction magnitude was less than that of n-heptane's replacement. Methane's addition slightly inhibited n-heptane's auto-ignition. The reaction time of n-heptane was obviously earlier than that of methane. N-heptane decomposition induced radical formation firstly, which triggered subsequent n-heptane's H-abstraction and the advance of methane's oxidation. At ultra-high-pressure low-temperature condition, increasing n-heptane's content enhanced negative temperature coefficient (NTC) behavior. The end time point of complete consumption of two fuels was the same. Low-temperature condition inhibited n-heptane decomposition, with n-heptane's H-abstraction dominating ignition process. • Ignition properties of CH4/n-C7H16 mixture was revealed by shock tube and mechanisms. • Active radicals formed from n-heptane's decomposition advanced methane's oxidation. • Methane's addition slightly retarded the ignition of pure n-heptane mixture. • The results provided ignition control method for natural-gas/diesel dual-fuel engine. [ABSTRACT FROM AUTHOR]

Submarine groundwater discharge (SGD) has been recognized as an important source of dissolved heavy metals to the coastal ocean. Bohai Bay, the second largest bay of Bohai Sea in China, is subjected to serious environmental problems. However, SGD and SGD-derived heavy metal fluxes in the bay are seldom reported. In this study, we present mass balance models considering the radium losses caused by recirculated seawater to estimate water age, SGD and SGD-derived heavy metal fluxes in Bohai Bay during May 2017. The water age is estimated to be 56.7–85.0 days based on tidal prism model. By combining water and salt mass balance models, submarine fresh groundwater discharge (SFGD) is estimated to be (3.5–9.3) × 107 m3 d−1. The SGD flux estimated by the radium mass balance models is (3.2–7.7) × 108 m3 d−1, an order of magnitude larger than the discharge of the Yellow River during the sampling period. SGD-derived heavy metal fluxes were estimated to be (0.2–6.0) × 107 mol d−1 for Fe, (1.2–2.7) × 107 mol d−1 for Mn, (3.0–8.2) × 105 mol d−1 for Zn, (2.7–7.4) × 104 mol d−1 for Cr and (0.6–1.8) × 103 mol d−1 for Cd, which are significantly higher than those from local rivers. This study reveals that SGD is a significant source of heavy metals (Mn, Zn and Fe) into Bohai Bay, which may have important influences on the metal budgets and ecological environments in coastal areas. Unlabelled Image • SGD was evaluated by coupling radium, salt and water mass balance models. • SGD-derived heavy metal fluxes into Bohai Bay, China were estimated. • SGD was a dominant source of dissolved Mn, Zn and Fe into the bay. [ABSTRACT FROM AUTHOR]

Near- and off-shore fresh groundwater resources become increasingly important with the social and economic development in coastal areas. Although large scale (hundreds of km) submarine groundwater discharge (SGD) to the ocean has been shown to be of the same magnitude order as river discharge, submarine fresh groundwater discharge (SFGD) with magnitude comparable to large river discharge is never reported. Here, we proposed a method coupling mass-balance models of water, salt and radium isotopes based on field data of 223Ra, 226Ra and salinity to estimate the SFGD, SGD. By applying the method in Laizhou Bay (a water area of ~6000 km2), we showed that the SFGD and SGD are 0.57 ~ 0.88 times and 7.35 ~ 8.57 times the annual Yellow River flux in August 2012, respectively. The estimate of SFGD ranges from 4.12 × 107 m3/d to 6.36 × 107 m3/d, while SGD ranges from 5.32 × 108 m3/d to 6.20 × 108 m3/d. The proportion of the Yellow River input into Laizhou Bay was less than 14% of the total in August 2012. Our method can be used to estimate SFGD in various coastal waters. [ABSTRACT FROM AUTHOR]