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In this paper, we propose a stochastic SIR epidemic model with vertical transmission and varying total population size. Firstly, we prove the existence and uniqueness of the global positive solution for the stochastic model. Secondly, we establish three thresholds λ 1 , λ 2 and λ 3 of the model. The disease will die out when λ 1 < 0 and λ 2 < 0 , or λ 1 > 0 and λ 3 < 0 , but the disease will persist when λ 1 < 0 and λ 2 > 0 , or λ 1 > 0 and λ 3 > 0 and the law of the solution converge to a unique invariant measure. Moreover, we find that when λ 1 < 0 some stochastic perturbations can increase the threshold λ 2 , while others can decrease the threshold λ 2 . That is, some stochastic perturbations enhance the spread of the disease, but others are just the opposite. On the other hand, when λ 1 > 0 , some stochastic perturbations increase or decrease the threshold λ 3 with different parameter sets. Finally, we give some numerical examples to illustrate obtained results. [ABSTRACT FROM AUTHOR]

The application of series dual burning rate grain can improve specific impulse of nozzleless solid rocket motor (NSRM). In this paper, burning-rate ratio is the ratio of main propellant burning rate and nozzle propellant burning rate in dual burning rate grain, which has significant influence on NSRM performance. Focusing on relationship between burning-rate ratio and motor performance, internal ballistics simulation of NSRM with different burning-rate ratios has been carried out. Results show that, with the increase of burning-rate ratio, total impulse grows monotonically, while maximum head pressure has two variation stages – the stable stage and the increasing stage. By analyzing the head pressure curves, it is known that maximum head pressure is almost equal to the higher one of initial stage head pressure (p1) and combustion ending stage head pressure (p2). Relationship between p2/p1 and burning-rate ratio has been established by linear fitting, and the critical burning-rate ratio, which is the maximum burning-rate ratio to ensure that maximum head pressure almost is kept invariant, has been obtained. Critical burning-rate ratio has no significant change when geometry size remains invariant. Utilizing critical burning-rate ratio in NSRM with series dual burning rate grain, specific impulse can be enhanced with nearly no sacrifice of maximum head pressure performance. These results can provide references for NSRM designing and optimizing. [ABSTRACT FROM AUTHOR]

• Unwanted on-target mutation occurs after CRISPR–Cas9 cleavage. • Assessment of comprehensive on-target outcomes is necessary. • Clinical genomic engineering requires quality controls to address safety concerns. CRISPR–Cas9 is a powerful tool for editing the genome and holds great promise for gene therapy applications. Initial concerns of gene engineering focus on off-target effects. However, in addition to short indel mutations (often <50 bp), an increasing number of studies have revealed complex on-target results after double-strand break repair by CRISPR–Cas9, such as large deletions, gene rearrangement, and loss of heterozygosity. These unintended mutations are potential safety concerns in clinical gene editing. Here, in this review, we summarize the significant findings of CRISPR–Cas9-induced on-target deleterious outcomes and discuss putative ways to achieve safe gene therapy. [ABSTRACT FROM AUTHOR]

In this article, based on the existing literature, we extend a deterministic delayed SIS epidemic model with vaccination to the stochastic version. First, we show that the solution of system is globally unique, positive and stochastically bounded. Then, constructing suitable Lyapunov function, we study the stochastic stability of system at the disease-free equilibrium. Moreover, the threshold R ̂ 0 which determines the extinction or persistence in time mean of the disease is proposed. When R ̂ 0 is less than 1, the disease will disappear; while R ̂ 0 is greater than 1, the disease will persist. Moreover, we study the existence of the ergodicity and the stationary distribution of the model, which can help us better understand the dynamic behavior and statistical characteristics of stochastic delayed biological models. Finally, we apply the results to hepatitis B in Chinese mainland. Using the nonlinear Least-Square method, we estimate the parameter of the model and obtain the threshold R ̂ 0 = 0.0556. We forecast that hepatitis B infections in Chinese mainland will drop to about 20 million in 2100 from 90 million in 2015, and give the probability densities of Hepatitis B infections each year. [ABSTRACT FROM AUTHOR]

• A new a deterministic and stochastic epidemic model with varying total population size is proposed. • The thresholds of the deterministic and stochastic epidemic model are established respectively. • Our methods can improve some existing results. • We carry out numerical and find a critical isolation rate 0.0217. • The empirical probability density are presented. In this paper, a stochastic and a deterministic SIS epidemic model with isolation and varying total population size are proposed. For the deterministic model, we establish the threshold R 0. When R 0 is less than 1, the disease-free equilibrium is globally stable, which means the disease will die out. While R 0 is greater than 1, the endemic equilibrium is globally stable, which implies that the disease will spread. Moreover, there is a critical isolation rate δ *, when the isolation rate is greater than it, the disease will be eliminated. For the stochastic model, we also present its threshold R 0 s. When R 0 s is less than 1, the disease will disappear with probability one. While R 0 s is greater than 1, the disease will persist. We find that stochastic perturbation of the transmission rate (or the valid contact coefficient) can help to reduce the spread of the disease. That is, compared with stochastic model, the deterministic epidemic model overestimates the spread capacity of disease. We further find that there exists a critical the stochastic perturbation intensity of the transmission rate σ *, when the stochastic perturbation intensity of the transmission rate is bigger than it, the disease will disappear. At last, we apply our theories to a realistic disease, pneumococcus amongst homosexuals, carry out numerical simulations and obtain the empirical probability density under different parameter values. The critical isolation rate δ * is presented. When the isolation rate δ is greater than δ *, the pneumococcus amongst will be eliminated. [ABSTRACT FROM AUTHOR]

This paper delves into the analysis of a stochastic epidemic model known as the susceptible–vaccinated–exposed–infectious–recovered (SVEIR) model, where transmission dynamics are governed by a nonlinear function. In the theoretical analysis section, by suitable stochastic Lyapunov functions, we establish that when the threshold value, denoted as R 0 s , falls below 1, the epidemic is destined for extinction. Conversely, if the reproduction number R 0 of the deterministic model surpasses 1, the model manifests an ergodic endemic stationary distribution. In the numerical simulations and data interpretation section, leveraging a graphical analysis with COVID-19 data, we illustrate that random fluctuations possess the capacity to quell disease outbreaks, underscoring the role of vaccines in curtailing the spread of diseases. This study not only contributes to the understanding of epidemic dynamics but also highlights the pivotal role of stochasticity and vaccination strategies in epidemic control and management. The inherent balance and patterns observed in epidemic spread and control strategies, reflect a symmetrical interplay between stochasticity, vaccination, and disease dynamics. [ABSTRACT FROM AUTHOR]

We investigate the blowup solutions to the Klein‐Gordon‐Schrödinger (KGS) system with power nonlinearity in spatial dimensions RN (N ≥ 2). Relying on a Lyapunov functional, we establish a perturbed virial‐type identity and prove the existence of blowup solutions for the system with a negative energy and small mass. Moreover, we obtain a new finite‐time blowup result of solutions to KGS system in the energy space by constructing a differential inequality. [ABSTRACT FROM AUTHOR]

In this paper, we study a stochastic SIS epidemic model with vertical infection. By constructing suitable stochastic Lyapunov function, we establish sufficient conditions for the existence of a stationary probability measure of the model. In addition, we also establish sufficient conditions for extinction and persistence of the disease. [ABSTRACT FROM AUTHOR]

Climate change mitigation requires the reduction of greenhouse gas (GHG) emissions. The majority of the discussions on climate change policy focus exclusively on the reduction of carbon dioxide (CO 2 ) emissions but ignore other important GHGs such as methane. This paper investigates the optimal choice of policy instruments under the joint consideration of CO 2 and methane in a dynamic setting with asymmetric information and pollutant correlations. We develop a dynamic programming model with two state variables and calibrate it to the global warming case. The results show that it is optimal to levy tax on both CO 2 and methane. A mixed strategy that implements a tax on CO 2 and a quota on methane is the second-ranked choice. [ABSTRACT FROM AUTHOR]

Road pricing can improve air quality by reducing and spreading traffic flows. Nevertheless, air quality does not depend only on traffic flows, but also on pollution dispersion. In this paper we investigate the effects of the temporal variation in pollution dispersion on optimal road pricing, and show that time-varying road pricing is needed to make drivers internalize the social costs of both time-varying congestion and time-varying pollution. To this end, we develop an ecological economics model that takes into account the effects of road pricing on daily commuting patterns. We characterize the optimal road pricing when pollution dispersion varies over the day and analyze its effects on traffic flows, arrival times, and the number of commuters by car. [ABSTRACT FROM AUTHOR]

In this paper, we present the threshold of a stochastic SIQS epidemic model which determines the extinction and persistence of the disease. Furthermore, we find that noise can suppress the disease outbreak. Numerical simulations are also carried out to confirm the analytical results. [ABSTRACT FROM AUTHOR]

As one of the most important instruments for reducing emissions from fossil fuels, taxes have been widely used in government battles against air pollution and climate change across the world. However, the pass-through of taxes and their effect on emissions are not evident in all situations. This study investigates the pass-through of diesel consumption taxes to retail prices and estimates the consequent effect on diesel consumption and carbon emissions in China. The results show that the pass-through rate of diesel taxes in China is around 0.49. Also, there is a significant effect of an oil company's market share on the pass-through rate. Based on the pass-through rate and estimated price elasticity, we conduct further estimations of the impact on diesel consumption and carbon emissions and find that the increase in the diesel consumption tax in 2014/2015 reduces 1.64% of annual diesel consumption and 0.096% of annual carbon emissions in China. • This study investigates the pass-through of diesel taxes to retail prices and the impact on carbon emissions in China. • Pass-through rate of the diesel tax is found to be around 0.49. • A high market share leads to a higher pass-through rate for an oil company. • The diesel tax adjustment in 2014/2015 in China reduces 0.096% of annual carbon emissions. [ABSTRACT FROM AUTHOR]

By using a general Ginzburg–Landau approach, we study the effects of external magnetic background on color–flavor-locked quark color-superconducting matter. The rotated magnetic field B ˜ is introduced, not only accounting for the unbroken symmetry with the rotated electric charge, but also resulting in new effects for the collective excitations such as the Nambu–Goldstone and Higgs modes. In particular, it is found that the masses of Higgs octet are no longer degenerated and part of them acquire the magnetic-induced contribution. To the leading order in the applied field, we construct an effective Ginzburg–Landau formalism through these B ˜ -related masses. As the application, we investigate magnetic responses of the non-Abelian vortices arising from color–flavor-locked symmetry breaking pattern. The B ˜ -field dependence of their spatial configurations and tension energies are calculated for the first time. [ABSTRACT FROM AUTHOR]

To simplify the complexity of moving boundary treatment in the two-phase flow numerical simulation and improve the computational accuracy of moving boundary treatment, a two-dimensional twophase flow model based on ALE method is established. The governing equations are discretized with the TVD-type MUSCL scheme to obtain a second order accuracy in finite volume form. A two-step and fourthorder Runge-Kutta method is used to solve the source terms. The dynamic mesh update method and numerical method are verified by a standard test with the exact solution. The numerical application on a large caliber guided projectile shows the complete development and the two-phase flow characteristics of the interior ballistic process. The calculated results are in good agreement with the experimental results. The effects of different ignition conditions on interior ballistic performance are investigated. The study lays a theoretical foundation for deep optimization of the interior ballistic performance and firing safety. [ABSTRACT FROM AUTHOR]

DNA performsa vital function as a carrier of genetic code, but in the field ofnanotechnology, DNA molecules can catalyze chemical reactions in thecell, that is, DNAzymes, or bind with target-specific ligands, thatis, aptamers. These functional DNAs with different modifications havebeen developed for sensing, imaging, and therapeutic systems. Thus,functional DNAs hold great promise for future applications in nanotechnologyand bioanalysis. However, these functional DNAs face challenges, especiallyin the field of biomedicine. For example, functional DNAs typicallyrequire the use of cationic transfection reagents to realize cellularuptake. Such reagents enter the cells, increasing the difficulty ofperforming bioassays in vivo and potentially damaging the cell’snucleus. To address this obstacle, nanomaterials, such as metallic,carbon, silica, or magnetic materials, have been utilized as DNA carriersor assistants. In this Account, we describe selected examples of functionalDNA-containing nanomaterials and their applications from our recentresearch and those of others. As models, we have chosen to highlightDNA/nanomaterial complexes consisting of gold nanoparticles, graphene oxides, and aptamer–micelles, and we illustrate the potentialof such complexes in biosensing, imaging, and medical diagnostics. [ABSTRACT FROM AUTHOR]

In this paper, a new theory of generalized thermoelasticity has been proposed by taking into account the general heat conduction law, which depends on the motion of the thermomass defined as the equivalent mass of phonon gas in dielectrics according to Einstein's mass-energy relation and involves the inertia effect on the time and space of the heat flux and temperature. The formulations are derived and given for anisotropic heterogeneous and isotropic homogenous materials. The uniqueness theorem of equations for the isotropic homogenous materials is proved. By comparison with the other theories of generalized thermoelasticity, the theory based on the motion of thermomass is more reasonable to predict the propagation of thermal and elastic waves in the microscale heat conduction conditions. [ABSTRACT FROM AUTHOR]

Abstract: Gold nanoparticles-based colorimetric assay possesses several unique advantages, and has been applied for a wide range of targets, varying from nucleic acids to different metal ions. However, due to the lack of proper coordinating ligand, gold nanoparticles-based colorimetric sensing system for Au3+ has not been developed so far. It is well-known that Au3+ could induce the oxidation transition of thiol compounds to disulfide compounds. In this article, for the first time we converted such thiol masking reaction into colorimetric sensing system for label-free detection of Au3+ via a target-controlled aggregation of nanoparticles strategy. In the new proposed sensing system, fluorosurfactant-capped gold nanoparticles were chosen as signal reporter units, while an Au3+-triggered oxidation of cysteine (Cys), which inhibited the aggregation of gold nanoparticles, acted as the recognition unit. By varying the amount of Cys, a tunable response range accompanied with different windows of color change could be obtained for Au3+, illustrating the universality of the sensing system for Au3+ samples with different sensitivity requirements. Under optimized condition, the proposed sensing system exhibits a high sensitivity towards Au3+ with a detection limit of 50nM, which is lower than previously reported spectroscopic methods. It has also been applied for detection of Au3+ in practical water samples with satisfactory result. [Copyright &y& Elsevier]

Abstract: In this work, we developed a new numerical approach for the establishment of strain gradient constitutive equations in heterogeneous materials with periodic microstructure through homogenization over a unit cell. To this end, we considered a periodic unit cell of finite size, including different homogenous phases and subjected to gradient remote loading. The local elasticity problem was solved by combining the theoretical asymptotic analysis with the Fast Fourier Transform (FFT) method. The asymptotic analysis allows the establishment of differential equations of different orders. These equations were resolved by using the FFT method. By using the homogenization procedure proposed in Li (2011a,b), intrinsic strain gradient constitutive relations can be constructed. This approach fulfils the severe exigency on accuracy of the high-order homogenization. Numerical simulations on examples with 1D and 2D microstructures showed that this approach is highly accurate and efficient. Discussions were completed on the mechanical implications of the strain gradient constitutive laws through the obtained numerical results. [Copyright &y& Elsevier]

Overall investigating into the current coal-gas outburst mechanisms at home and abroad, we analyzed the key factors influencing coal-gas outburst from the perspective of gas geology, such as deformed coal, gas and tectonism. Based on those results, the geological control mechanism of coal-gas outburst centering on gas outburst coal is tentatively proposed. It is pointed out the coal-gas outburst being as follows: in the face of coal wall, gas outburst coal with a certain thickness is extended to expansion and failure due to unloading mining, and permeability of coal seam increases ; because of abundant coal bed methane (CBM) desorbing fast, a mixture of CBM and coal particles with higher kinetic energy has been formed instantly in front of the coal wall, like an explosives, and it results in avalanche damage of coal body. Taken the "10 ⋅ 20" mining calamity for example, the geological-control case for coal-gas outburst had been analyzed, and revealed the distribution of gas outburst coal based on gas-geological characteristics of coal mines in China's Xinjiang Uighur Autonomous Region. [ABSTRACT FROM AUTHOR]

An improved two-phase flow model is established to simulate the interior ballistic characteristics of modular propellant charge. In this model, the constraint of the walls of modules on gas flow is taken into account. The rupture rule of combustible case and the flame spreading between different modules are also considered in the improved model. This model turned out to be reliable by comparing the numerical results with the experimental data. It can be used to predict the development of pressure waves and to diagnose the interior ballistic performance of modular propellant charge systems. The simulation results show that the flame spreads slower because the gas is constrained by the bottom walls of the center-tube. The combustible cases are ruptured in sequence, the time when the combustible cases begin to rupture until all the cases rupture is affected by the strength of the modular case and the ignition core. [ABSTRACT FROM AUTHOR]

A contamination prevention method using jet flow was proposed to protect the optical window in laser ignition system from attachment of combustion remains of propellants and decrease of transparence. The pressure in chamber and gas flow between the chamber and the cavity were analyzed by using interior ballistics calculation. The mathematical model of the particle movement in the chamber was established and calculated. The calculation and simulation results indicate that the new proposed method is effective to protect the optical window, the jet flow interference can reduce the particles reaching to the optical window area effectively. The structural parameters are optimized for guns with different calibers based on the simulations. A screen tube is proved to be useful to enhance the protection effect. The increases of the length of cavity or the angle of diverting orifice can lead to a better protection. [ABSTRACT FROM AUTHOR]

Abstract: Microbial infection is an obstacle of burn treatment. However, little is known on what types of microbial infection dominate in the burn center and how the dynamic change of those microorganisms occurs during the past several years in China. We conducted a retrospective study of nosocomial infection (NI) in a large burn center to analyze the spectrum and antimicrobial resistance of microbial isolates from January 2003 to December 2010. We studied 989 isolates from 677 patients who had signs and symptoms of infection 48h after admission. The number of NIs per 100 admissions was 10.9. The commonest isolates were Pseudomonas aeruginosa (23.1%), Staphylococcus aureus (18.7%), and Candida (11.4%). The result indicated that the numbers of patients with Acinetobacter sp. infection increased (P =0.004), but with Proteus mirabilis infection decreased (P =0.004). The isolated Acinetobacter sp. and P. aeruginosa were consistently highly resistant to almost all antibiotics tested. Notably, more frequent Acinetobacter sp. isolates appeared to be resistant to amikacin, gentamicin, tobramycin, ceftazidim, piperacillin, tazobactam, levofloxacin, and ciprofloxacin and more frequent Escherichia coli isolates were resistant to ceftazidime and aztreonam at the late time period although the P. aeruginosa and E. coli isolates were sensitive to less used ciprofloxacin and piperacillin/tazobactam. The increased rates of drug-resistant isolates in the later period might be associated with regular prophylactic therapy with antibiotics. [Copyright &y& Elsevier]

According to the limitation of the interior ballistic charge design with genetic algorithms and some other direct optimization methods, which has complex evolution operators such as crossover and mutation or has poor perferance in solution accuracy and speed, a modified particle swarm optimizer is proposed which is based on a geometrical way and a fuzzy multi-objective optimization. The modified particle swarm optimizer is used to both single-objective and multi-objective optimization problems of interior ballistic charge design for a guided projectile. The solution results show that the modified particle swarm optimizer has a better convergence rate and accuracy than the original particle swarm optimizer and other ever used optimization methods. Combined with deterred propellant technique, the interior ballistic charge design for a guided projectile is optimized by the modified particle swarm optimizer. The optimization results improve the interior ballistic performance and launch safety and provide theoretical direction for the interior ballistic charge design of guided projectile. [ABSTRACT FROM AUTHOR]

Kisspeptin plays an important role in puberty and subsequent fertility by activating its receptor, G-protein-coupled receptor 54 (GPR54), and increasing cytoplasmic free Ca2+ concentration ([Ca2+]i) and gonadotropin-releasing hormone (GnRH) secretion in GnRH neurons. Yet the mechanism by which kisspeptin increases [Ca2+]i in GnRH neurons remains to be fully elucidated. In other neurons, voltage-gated Ca2+ channel (VGCC) activity has been shown to be inversely related to [Ca2+]i. We used whole-cell patch-clamp recording to examine the effects of kisspeptin-10 (KP-10) on VGCC activity evoked by step depolarizations in GnRH neurons in brain slices from pubertal male GnRH-green fluorescent protein transgenic mice. Prolonged (>30 s) KP-10 application inhibited Ca2+ currents. The GPR54 antagonist peptide 234, chelation of intracellular Ca2+ by 1,2-bis(2-aminophenoxy)ethane N,N,N′,N′-tetraacetic acid, substitution of Ba2+ for Ca2+, the calmodulin antagonists calmidazolium and trifluoperazine, the phospholipase C inhibitor edelfosine, the canonical transient receptor potential (TRPC) channel and inositol 1,4,5-trisphosphate receptor (IP3R) antagonist 2-APB, the TRPC channel antagonist BTP2 and the endoplasmic reticulum Ca2+-ATPase blocker cyclopiazonic acid each prevented inhibition. The IP3R antagonists caffeine (10 μM), heparin and intracellular 2-APB prevented inhibition to a lesser extent. The ryanodine receptor (RyR) antagonists ryanodine and dantrolene prevented inhibition, and the RyR agonist caffeine (30 mM) mimicked the effects of KP-10 on Ca2+ currents. Our results suggest that kisspeptin induces Ca2+ influx through TRPC channels and Ca2+ release via IP3Rs and RyRs, and that this is followed by Ca2+/CaM-dependent inhibition of VGCCs. Copyright © 2012 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Series chamber is a new technology on the basis of the mature technology of solid propellant. It can improve the propeller' s kinetic energy through rebuilding the existed guns. It is important to the weapons' performance improvement. The two phase flow model of the interior ballistics process of 140 mm series chamber gun is established and simulated by MacCormack scheme. In addition, the completed programming has been used to analyze the influence of main-secondary powder proportion, ignition delay of secondary power and piston mass on interior ballistics performance. The result shows that the new technology can improve propeller's velocity while not adding chamber's pressure. [ABSTRACT FROM AUTHOR]

A unified generalized thermoelasticity solution for the transient thermal shock problem in the context of three different generalized theories of the coupled thermoelasticity, namely: the extended thermoelasticity, the temperature-rate-dependent thermoelasticity and the thermoelasticity without energy dissipation is proposed in this paper. First, a unified form of the governing equations is presented by introducing the unifier parameters. Second, the unified equations are derived for the thermoelastic problem of the isotropic and homogeneous materials subjected to a transient thermal shock. The Laplace transform and inverse transform are used to solve these equations, and the unified analytical solutions in the transform domain and the short-time approximated solutions in the time domain of displacement, temperature and stresses are obtained. Finally, the numerical results for copper material are displayed in graphical forms to compare the characteristic features of the above three generalized theories for dealing with the transient thermal shock problem. [ABSTRACT FROM AUTHOR]

Laser ignition technology is a new launch technology. The numerical simulation is carried out to investigate the influence of multi-point laser ignition to the pressure wave and abnormal combustion of the propellants. A two-dimensional two-phase flow model of multi-point laser ignition in a short-barrel gun is established. Numerical simulation is conducted by MacCormack predictor-corrector scheme and the movable boundary conditions are obtained by movable control volume method. The numerical calculation results are consistent with those of the experiments. It has good value for laser ignition system design. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, for the first time, Cu nanoparticles (CuNPs) were prepared by seed-mediated growth method with Au nanoparticles (AuNPs) playing the role of seeds. Carbon nanotubes (CNTs) and AuNPs were first dropped on the surface of glassy carbon (GC) electrode, and then the electrode was immersed into growth solution that contained CuSO4 and hydrazine. CuNPs were successfully grown on the surface of the CNTs. The modified electrode showed a very high electrochemical activity for electrocatalytic oxidation of glucose in alkaline medium, which was utilized as the basis of the fabrication of a nonenzymatic biosensor for electrochemical detection of glucose. The biosensor can be applied to the quantification of glucose with a linear range covering from 1.0×10−7 to 5×10−3 M and a low detection limit of 3×10−8 M. Furthermore, the experiment results also showed that the biosensor exhibited good reproducibility and long-term stability, as well as high selectivity with no interference from other oxidable species. [Copyright &y& Elsevier]

Objective: Leukemia-initiating cells (LICs) have been the subject of considerable investigation because of their ability to self-renew and maintain leukemia. Thus, selective targeting and killing of LICs would provide highly efficient and novel therapeutic strategies. Here we explored whether we could use a canine leukemia cell line (G374) derived from a dog that received HOXB4-transduced repopulating cells to study leukemia in the murine xenograft model and the dog. Materials and Methods: G374 cells were infused in dogs intravenously and in nonobese diabetic/severe combined immunodeficient and nonobese diabetic/severe combined immunodeficient/IL2Rγnull mice either intravenously or directly into the bone cavity. Animals were bled to track engraftment and proliferation of G374 cells, and were sacrificed when they appeared ill. Results: We found that canine LICs are capable of sustained in vitro self-renewal while maintaining their ability to induce acute myeloid leukemia, which resembles human disease in both dogs and mice. Furthermore, we developed a novel strategy for the quantification of LIC frequency in large animals and showed that this frequency was highly comparable to that determined by limited dilution in mouse xenotransplants. We also demonstrated, using single-cell analysis, that LICs are heterogeneous in their self-renewal capacity and regenerate a leukemic cell population consistent with a hierarchical leukemia model. Conclusions: The availability of this novel framework should accelerate the characterization of LICs and the translation of animal studies into clinical trials. [Copyright &y& Elsevier]

A ratiometric fluorescent zinc probe 1 of carboxamidoquinoline with a carboxylic acid group was designed and synthesised. Probe 1 exhibits high selectivity for sensing Zn2+; about a 13-fold increase in fluorescence emission intensity and an 82 nm red-shift of fluorescence emission are observed upon binding Zn2+ in EtOH/H2O (1 : 1, V/V) solution. The ratiometric fluorescence response is attributed to the 1 : 1 complex formation between probe 1 and Zn2+ which has been utilised as the basis for the selective detection of Zn2+. The analytical performance characteristics of the proposed Zn2+-sensitive probe were investigated. The linear response range covers a concentration range of Zn2+ from 2.0 × 10-6 to 5.0 × 10-5 mol L-1 and the detection limit is 2.7 × 10-7 mol L-1. The determination of Zn2+ in both tap and river water samples shows satisfactory results. [ABSTRACT FROM AUTHOR]

Quinoline-appended rhodamine B thiohydrazide based fluorescent probe was designed and applied in fluorescent detections of mercury ions in both aqueous solution and living cells. The signal change of the probe is based on a specific metal ion induced reversible ring-opening mechanism of a rhodamine B thiohydrazide. The probe exhibits a dynamic response concentration range for Hg2+ from 1.0 × 10-8 to 1.0 × 10-5 M with a detection limit of 8.5 × 10-9 M. The fluorescent probe is pH independent in medium condition and exhibits high selectivity over other common metal ions. [ABSTRACT FROM AUTHOR]

Abstract: The differential susceptibility SIR epidemic model with stage structure and pulse vaccination is introduced. By the comparison theorem, some sufficient conditions for the globally attractivity of an infection-free periodic solution and the permanence of this system are presented. Two numerical simulations are also given to illustrate our main results. [Copyright &y& Elsevier]

The energy security situations of many oil-consuming countries have become worse because of greater uncertainty in the world market. This is especially true for developing countries such as China and India, which face greater risks because of their lack of strategic petroleum reserves (SPRs). China and India both embarked on SPR planning during the past few years, with the expectation of eliminating the effects of future oil-supply disruptions. In the world oil market, there are probably interactions between the SPR policies, including acquisition and release strategies, of the two biggest developing countries. Understanding how their SPR policies interact and vary with important factors would help decision-makers develop more effective policies. In this paper, a stochastic dynamic Nash game model has been developed, in which the players compete with each other and make individual decisions to minimize their expected total SPR cost. Using the model, it was possible to obtain, for a few cases, illustrative results for each player''s strategies for building up and drawing down strategic oil reserves These results indicate that the buildup and drawdown policies of the players are related to many factors, including oil-market elasticity, unit stockpile holding costs, disruption and disruption-continuation probabilities, maximum reserve capacities, and other factors. [Copyright &y& Elsevier]

Abstract: A fluorescent probe 1 for Hg2+ based on a rhodamine–coumarin conjugate was designed and synthesized. Probe 1 exhibits high sensitivity and selectivity for sensing Hg2+, and about a 24-fold increase in fluorescence emission intensity is observed upon binding excess Hg2+ in 50% water/ethanol buffered at pH 7.24. The fluorescence response to Hg2+ is attributed to the 1:1 complex formation between probe 1 and Hg2+, which has been utilized as the basis for the selective detection of Hg2+. Besides, probe 1 was also found to show a reversible dual chromo- and fluorogenic response toward Hg2+ likely due to the chelation-induced ring opening of rhodamine spirolactam. The analytical performance characteristics of the proposed Hg2+-sensitive probe were investigated. The linear response range covers a concentration range of Hg2+ from 8.0×10−8 to 1.0×10−5 molL−1 and the detection limit is 4.0×10−8 molL−1. The determination of Hg2+ in both tap and river water samples displays satisfactory results. [Copyright &y& Elsevier]

Objective: There are currently no large animal models to study the biology of leukemia and development of novel antileukemia therapies. We have previously shown that dogs transplanted with homeobox B4 (HOXB4)−transduced autologous CD34+ cells developed myeloid leukemia associated with HOXB4 overexpression. Here we describe the transmission, engraftment, and expansion of these canine leukemia cells into two genetically unrelated, immunosuppressed dogs. Materials and Methods: Two dogs immunosuppressed after major histocompatibility complex−haploidentical hematopoietic cell transplantation and exhibiting mixed donor−host chimerism were accidentally infused trace amounts of HOXB4-overexpressing leukemia cells from a third-party dog. Results: Six weeks after infusion of HOXB4-overexpressing leukemia cells, these two dogs rapidly developed myeloid leukemia consisting of marrow and organ infiltration, circulating blasts, and, in one dog, chloromatous masses. Despite neither of these dogs sharing any dog leukocyte antigen haplotypes with the sentinel case, the HOXB4-transduced clones engrafted and proliferated without difficulty in the presence of immunosuppression. Chimerism studies in both dogs confirmed that donor and, in one case, host hematopoietic cell engraftment was lost and replaced by third-party HOXB4 cells. Conclusions: The engraftment and expansion of these leukemia cells in dogs will allow studies into the biology of leukemia and development and evaluation of novel antileukemia therapies in a clinically relevant large animal model. [Copyright &y& Elsevier]

Abstract: In the present paper, we describe the fabrication and analytical characteristics of fluorescence-based zinc ion-sensing glass slides. To construct the sensor, a benzoxazole derivative 4-benzoxazol-2′-yl-3-hydroxyphenyl allyl ether (1) with a terminal double bond was synthesized and copolymerized with 2-hydroxyethyl methacrylate (HEMA) on the activated surface of glass slides by UV irradiation. In the absence of Zn2+ at pH 7.24, the resulting optical sensor emitted fluorescence at 450nm via excited-state intramolecular proton transfer (ESIPT). Upon binding with Zn2+, the ESIPT process was inhibited resulting in a 46nm blue-shift of fluorescence emission. Thus, the proposed sensor can behave as a ratiometric fluorescent sensor for the selective detection of Zn2+. In addition, the sensor shows nice selectivity, good reproducibility and fast response time. Cd2+ did not interfere with Zn2+ sensing. The sensing membrane demonstrates a good stability with a lifetime of at least 3 months. The linear response range covers a concentration range of Zn2+ from 8.0×10−5 to 4.0×10−3 mol/L and the detection limit is 4.0×10−5 mol/L. The determination of Zn2+ in both tap and river water samples shows satisfactory results. [Copyright &y& Elsevier]

Abstract: N-Methyl-α,β,γ,δ-tetraphenylporphine (NMTPPH) has been used to detect trace amount of zinc ions in ethanol–water solution by fluorescence spectroscopy. The fluorescent probe undergoes a fluorescent emission intensity enhancement upon binding to zinc ions in EtOH/H2O (1:1, v/v) solution. The fluorescence enhancement of NMTPPH is attributed to the 1:1 complex formation between NMTPPH and Zn(II) which has been utilized as the basis for the selective detection of Zn(II). The linear response range covers a concentration range of Zn(II) from 5.0×10−7 to 1.0×10−5 mol/L and the detection limit is 1.5×10−7 mol/L. The fluorescent probe exhibits high selectivity over other common metal ions except for Cu(II). [Copyright &y& Elsevier]

Abstract: We report on the synthesis and self-assembly of two novel types of hydrazide derivatives, e.g. 1,4-bis[(3,4,5-trialkoxyphenyl)-dihydrazide]-2,5-diethylphthalate (C-Tn, n =7, 10, 12 and 16) and N’,N’-bis[3,4,5-tris(dodecyloxy)benzamido]-pyromellitic diimide (BI-C-T12). They were confirmed to exhibit strong gelation ability in several apolar organic solvents, such as benzene, 1,2-dichloroethane and chloroform. SEM images of the xerogels revealed that the gels consist of twist fibrous aggregates. Both FT-IR and 1H NMR studies confirmed that the intermolecular hydrogen bonding and van der Waals interactions were the major driving forces for the self-assembly of the molecules during gelling. [Copyright &y& Elsevier]

Abstract: A new fluorescent chemosensor for sensing Co(II) using di(2-picolyl)amino (DPA) as a recognition group and quinazoline as a reporting group has been synthesized and characterized. The quinazoline derivative contains an intramolecular hydrogen bond, which would undergo excited-state intramolecular proton transfer (ESIPT) at illumination. The fluorescence quenching is attributed to cation-induced inhibition of ESIPT, which constitutes the basis for the determination of Co(II) with the prepared chemosensor. The fluorophore forms 1:1 cobalt(II) complex with the logarithm of apparent dissociation constant log K a =6.8. The analytical performance characteristics of the proposed Co(II)-sensitive sensor were investigated. The chemosensor exhibits a linear response toward Co(II) in the concentration range 3.2×10−8 to 1.4×10−6 M, with a working pH range from 7.0 to 9.5 and high selectivity. [Copyright &y& Elsevier]

Abstract: A porphyrin derivative (1), containing two 2-(oxymethyl)pyridine units has been designed and synthesized as chemosensor for recognition of metal ions. Unlike many common porphyrin derivatives that show response to different heavy metal ions, compound 1 exhibits unexpected ratiometric fluorescence response to Zn2+ with high selectivity. The response of the novel chemosensor to zinc was based on the porphyrin metallation with cooperating effect of 2-(oxymethyl)pyridine units. The change of fluorescence of 1 was attributed to the formation of an inclusion complex between porphyrin ring and Zn2+ by 1:1 complex ratio (K =1.04×105), which has been utilized as the basis of the fabrication of the Zn2+-sensitive fluorescent chemosensor. The analytical performance characteristics of the proposed Zn2+-sensitive chemosensor were investigated. The sensor can be applied to the quantification of Zn2+ with a linear range covering from 3.2×10−7 to 1.8×10−4 M and a detection limit of 5.5×10−8 M. The experiment results show that the response behavior of 1 to Zn2+ is pH-independent in medium condition (pH 4.0–8.0) and show excellent selectivity for Zn2+ over transition metal cations. [Copyright &y& Elsevier]

Abstract: The synthesis, optical properties, electrochemical properties, electronic structures and applications in electroluminescent device of three series of 1,3,4-oxadiazole derivatives, 1,4-bis[(4-methylphenyl)-1,3,4-oxadiazolyl]phenylene (OXD1), 5,5′-di-(4-methyl)-2,2′-p-(2,5-bisalkoxyphenylene)-bis-1,3,4-oxadiazole (OXD2–n ) and 1,4-bis[(4-alkoxyphenyl)-1,3,4-oxadiazolyl]phenylene (OXD3–n ) are reported. The molecular structures of the oxadiazole compounds were confirmed by FT-IR, 1H NMR spectroscopy and elemental analysis. The optical and electrochemical properties of the compounds were investigated by UV–vis absorption and photoluminescence spectroscopy as well as cyclic voltammetry. The results show that introduction of two alkoxy groups whose electron-donating ability is stronger than that of methyl groups increases the electron density of the conjugated segment of OXD2–n (with side-on alkoxy substituents) and OXD3–n (with end-on alkoxy substituents), and thus leads to the absorption maximum bathochromic-shift compared to that of OXD1. The HOMO and LUMO energy levels of the compounds studied are in the range of −2.78 to −2.89 and −5.75 to −6.20eV. Calculations on the representative compounds by the Dmol3 package of MS Modeling 3.0 revealed that the increase of energy levels in both OXD2–n and OXD3–n was due to the change of the frontier molecular orbital distribution in the central benzene ring. The light-emitting devices have been fabricated using blends of MEH-PPV and these compounds as emissive layers, among which, maximum brightness up to 11810cdm−2 (8.5V) has been observed, which is 40 times brighter than that with MEH-PPV. The result of the devices suggested that oxadiazole derivatives studied function well as electron-transporting materials and can be used in LEDs, and thus to enhance the efficiency of LEDs. [Copyright &y& Elsevier]

Abstract: In this paper, 2-(2′-hydroxy-phenyl)-4(3H)-quinazolinone (HPQ), a typical compound that exhibits excited state intramolecular proton transfer (ESIPT) reaction and possesses good photophysical properties, is synthesized and used as fluoroionophore for Fe3+ sensitive optochemical sensor. The decrease of fluorescence intensity of HPQ membrane upon the addition of Fe3+ was attributed to the blocking of ESIPT reactions of HPQ and quenching its fluorescence. The effect of the composition of the sensing membrane was studied, and experimental conditions were optimized. The sensor shows a linear response toward Fe3+ in the concentration range of 7.1×10−7 M to 1.4×10−4 M with a limit of detection of 8.0×10−8 M, and a working pH range from 2.5 to 4.5. It shows excellent selectivity for Fe3+ over a large number of cations such as alkali, alkaline earth and transitional metal ions. The proposed sensor is applied to the determination of the content of iron ions in pharmaceutical preparations samples with satisfactory results. [Copyright &y& Elsevier]

Abstract: An amide-linked 2,6-bis{[(2-hydroxy-5-tert-butylbenzyl)(pyridyl-2-methyl)-amino]-methyl}-4-methylphenol-ruthenium(II) tris(bipyridine) 2PF6 − complex, 1, was first used to recognize Co(II) in EtOH/H2O (1:1, v/v) solution, with the ruthenium(II) tris(bipyridine) moiety selected as a fluorophore and the multi-substituted phenol unit chosen as a receptor. The fluorescence quenching of 1 was attributed to the formation of an inclusion complex between multi-substituted phenol unit and Co(II) by 1:1 complex ratio (K =2.5×105), which has been utilized as the basis of the fabrication of the Co(II)-sensitive fluorescent chemosensor. The analytical performance characteristics of the proposed Co(II)-sensitive chemosensor were investigated. The sensor can be applied to the quantification of Co(II) with a linear range covering from 1.0×10−7 to 5.0×10−5 M and a detection limit of 5×10−8 M. The experiment results show that the response behavior of 1 to Co(II) is pH-independent in medium condition (pH 4.5–9.5) and show excellent selectivity for Co(II) over transition metal cations except Cu(II). The chemosensor has been used for determination of Co(II) in water samples. [Copyright &y& Elsevier]

Abstract: This paper describes a copper selective optical chemical sensor based on static quenching of the fluorescence of 2-(2′-hydroxyphenyl)benzoxazole entrapped in a poly(vinyl chloride) (PVC) membrane. The effect of the composition of the sensing membrane was studied, and experimental conditions were optimized. The sensors exhibit stable response over the concentration range from 4.0×10−8 M to 5.0×10−5 M Cu2+ at pH 4.0–6.5, and a high selectivity. The response time for Cu2+ with concentration ≤5×10−6 M is less than 7min. The optode can be regenerated using 0.1M HCl and acetate buffer solution. The sensor has been used for direct measurement of copper content in river water samples with a relative error less than 4% with reference to that obtained by atomic absorption spectrometry. [Copyright &y& Elsevier]

Abstract: A new highly selective silver(I) electrode was prepared with a PVC membrane using 5,10,15-tris(pentafluorophenyl)corrole as an electroactive material, 2-nitrophenyl octyl ether (o-NPOE) as a plasticizer and sodium tetraphenylborate (NaTPB) as an additive in the percentage ratio of 3:3:62:32 (corrole:NaTPB:o-NPOE:PVC, w:w). The electrode exhibited linear response with a near Nernstian slope of 54.8mV/decade within the concentration range of 5.1×10−6 to 1.0×10−1 M silver ions, with a working pH range from 4.0 to 8.0, and a fast response time of <30s. Selectivity coefficients for Ag(I) relative to a number of interfering ions were investigated. The electrode is highly selective for Ag(I) ions over a large number of mono-, bi-, and tri-valent cations. Common interferents like Hg2+ and Cd2+ show very low interfering effect on the silver assay, which is valuable property of the proposed electrode. Several electroactive materials and solvent mediators have been compared and the experimental conditions were optimized. The sensor was applied to the determination of silver in real ore samples with satisfied results. [Copyright &y& Elsevier]

Previous studies showed that progesterone receptor (PR), one of the hormone receptor superfamily, was only connected with the sex-correlated cancers such as breast cancer, endometrial cancer, prostate cancer, etc. This article deals with the PR gene in leukemia. We investigated the methylation status and the expression of the two different PR isoforms, PRA and PRB, in three leukemia cancer cell lines using methylation-specific polymerase chain reaction (MSP-PCR) and reverse transcription-PCR. The correlation of PR methylation and expression together with DNA methyltransferase (DNMT1) was further studied. We found that DNMT1 is required to maintain CpG methylation and aberrant gene silencing of PR gene in human leukemia cancer cells. The activity of 5-aza-2′-deoxycytidine in demethylation and gene reactivation may be through depleting cellular DNMT1 levels. In addition, extensive methylation of PRA and PRB was also observed in leukemia samples. Our results suggest that PR CpG island aberrant hypermethylation could be one molecular and genetic alteration in leukemia. [Copyright &y& Elsevier]

In this work, a set of J–Mp based criteria is proposed to assess the bifurcation angle of an elastic–plastic crack in plane strain under mixed mode loading. We first establish a criterion in order to study the competition between the tensile fracture (T-type fracture) and the shear fracture (S-type fracture) in the frame of RKR conception [J. Mech. Phys. Solids 21 (1973) 395]. Based on the generalized HRR [ASTM STP 560 (1974) 187] solution and on the knowledge of the mixity parameter Mp, the RKR based criterion is transformed into a J–Mp based criterion. When the crack grows in tensile manner, the maximum circumferential stress criterion is adopted to determine the crack bifurcation angle. When the crack grows in shear manner, the traditional theory of plasticity, according to which the plastic flow develops essentially along one of the slip bands immediately ahead of the crack tip, is used to determine the crack growth direction. All these proposed criteria are given as function of the mixity parameter Mp and the hardening exponent n of the material. Finally, we carry out some numerical computations by applying the proposed criteria and then compare the obtained results with experimental data gathered in literature. It is shown that these criteria are physically reasonable and highly accurate. Another advantage is that the parameters used are easy to identify numerically and experimentally, therefore, these criteria are simple to apply in engineering structures. [Copyright &y& Elsevier]

We evaluate the medium effects in nucleon which can induce an asymmetry of the strange sea. The short-distance effects determined by the weak interaction can give rise to δm ≡ Δm[SUBs] - Δm[SUBs] where Δ[SUBs(&ssline;)] is the medium-induced mass of strange quark by a few KeV at most, but the long-distance effects by strong interaction could be sizable. [ABSTRACT FROM AUTHOR]

Background: The cryopreservation of HPCs in DMSO has been practiced by cord blood (CB) banks worldwide. Inevitably, some detriment to biologic function occurs as the result of freezing injuries and DMSO toxicity. Trehalose, a disaccharide, is a natural cryoprotectant in organisms capable of surviving extreme dehydration and cold. The objective of this study was to establish the cryopreservation of CB under preclinical conditions using trehalose as a supplement to DMSO.Study Design and Methods: In a preclinical protocol, the effects of 5-percent trehalose with 10-percent DMSO or 5-percent DMSO on the cryopreservation of CB MNCs or nucleated cells (NCs) were further evaluated. The read-out system consisted of a panel of HPCs: early progenitors (CFU-GEMM, long-term culture-initiating cells [LTC-IC]) and committed progenitors (CFU-GM, CFU/BFU-E, CFU-megakaryocyte [CFU-MK]). The homing and engraftment capacity of these cells were assessed in nonobese diabetic (NOD)-SCID mice.Results: Trehalose increased the recoveries of CFU-GM, CFU/BFU-E, CFU-GEMM, and LTC-IC by over 7.25 percent (mean), 11.9 percent, 19.2 percent, and 12.9 percent, respectively, when compared with those in paired CB samples cryopreserved in 10-percent DMSO. Freezing and thawing reduced the yields of CFU-MK by 35.5 percent (mean) and 28.4 percent in MNC and NC samples, respectively, and the inclusion of 5-percent trehalose significantly retrieved these progenitor cells to over 90 percent of fresh samples. The improved recovery of functional HPLs was reflected by their multilineage engraftment in NOD-SCID mice.Conclusion: Trehalose at 5 percent significantly ameliorates the cryopreservation of CB progenitor cells at a preclinical protocol. The increased recoveries of these cells might potentially improve the engraftment outcomes of CB transplants. [ABSTRACT FROM AUTHOR]

An array of piezoelectric quartz crystal sensors (PQCs) has been prepared for analyzing organic vapor mixtures. The circuit of oscillators has been modified and optimized to circumvent the problems associated with mutual interference among different oscillators connecting to sensors in the array. Organic coating materials were clustered into four groups according to their polarity and compounds representing different groups were selected including silicone OV-101, silicone OV-17, silicone OV-275, span 85, and polyethylene glycol 1000. The sensor array constructed gives characteristic response patterns for different organic vapors such as methanol, 1,2-dichloroethane, benzene and cyclohexane. The feasibility of using the sensor array for analysis of binary and tertiary mixtures has been tested by using PLS and MLR data treatment algorithms. [Copyright &y& Elsevier]