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The analysis of the real-time simultaneous measurement data of the sand flux and wind speed fluctuations in the aeolian sand is carried out. Our results show that in the aeolian sand, the stream-wise wind speed fluctuations with a period (T) greater than 30 s has a small contribution to the turbulent kinetic energy, but its dominant sand flux plays an important role in the sand flux fluctuation intensity. Sand flux fluctuations (T > 30 s) with particle size smaller than 200 μm respond well to the stream-wise wind speed fluctuations. Sand flux fluctuations at different height (T > 30 s) have a higher correlation. Sand flux fluctuations with T < 30 s are not only poorly correlated along the height, but also poorly correlated with the sand flux fluctuations of different particle sizes. The results indicate that if the aeolian sand model is to be used to predict the spatial distribution of sand flux along the stream-wise direction, the stream-wise wind speed fluctuation with T > 30 s need to be considered in the model. The results of this paper have important guiding significance for the accurate prediction of dust storms and the design of sand control measures. [ABSTRACT FROM AUTHOR]

The multi-scale characteristics of the spatial distribution of space charge density (ρz) that determines the vertical electric field during a dust storm are studied based on field observation data. Our results show that in terms of ρz fluctuation on a weather scale, change of ρz with PM10 concentration approximately satisfies a linear relationship, which is consistent with the results of Zhang and Zhou (Nat Commun 11(1):1–12, 2020). The ρz between 10 and 15 m is small, and the ρz below 10 m is smaller than that above 15 m. Moreover, there will be a distribution feature where the negative polarity area and the positive polarity area alternately appear, that is, a stratification structure. For large-scale ρz fluctuation, its contribution to the fluctuation intensity cannot be ignored, and the correlation between ρz and PM10 concentration at different heights is poor. In addition, the ρz distribution below 14.65 m and above 14.65 m belongs to different structures. The spatial distribution corresponding to the large-scale ρz fluctuation shows a mosaic-like distribution characteristic. That is, not only does stratification occur in the vertical direction, but the positive polarity area and the negative polarity area alternate in the stream-wise direction. This means that the distribution of large-scale space charges will cause the uneven distribution of the vertical electric field along the stream-wise direction, and this effect is more obvious above 15 m. [ABSTRACT FROM AUTHOR]

Microplastics (MPs) pollution has been extensively investigated in natural fishery waters, but studies on intensive aquaculture systems are scarce. Here, the occurrence and properties of MPs were investigated and compared between four different aquaculture systems nearby the Yangtze Estuary. The average MPs concentration was in order of recirculating aquaculture system (RAS, 1.67 particles/L) < aquarium (2.47 particles/L) < cement pond (10.09 particles/L) < earthen pond (13.81 particles/L). Compared to fragment MPs, fiber was the more abundant shape in aquarium (85.88%), RAS (77.61%) and earthen pond (68.13%). A total of six colors were found in four systems. The black MPs accounted for 56.86% and 47.45% in aquarium and RAS system, respectively. The high proportion of blue MPs was found in cement pond (37.65%) and earthen pond (40%). The most MPs sizes observed in the four systems were 43% of 50–300 μm MPs in aquarium; 44% and 30.19% of 300–1000 μm MPs in RAS and cement pond, respectively; and 30.19% of 3000–5000 μm MPs in earthen pond. For polymers, polypropylene occupied 47.83% in aquarium and RAS, 41.46% in cement pond and 27.79% in earthen pond. Proportion of rayon was highest in RAS (60.87%) and 34.04% of nylon was found in earthen pond. These results could provide scientific reference for further traceability and removal of MPs in different aquaculture systems. [ABSTRACT FROM AUTHOR]

Pseudocapacitance holds great promise for improving energy densities of electrochemical supercapacitors, but state-of-the-art pseudocapacitive materials show capacitances far below their theoretical values and deliver much lower levels of electrical power than carbon-based materials due to poor cation accessibility and/or long-range electron transferability. Here we show that in situ corundum-to-rutile phase transformation in electron-correlated vanadium sesquioxide can yield nonstoichiometric rutile vanadium dioxide layers that are composed of highly sodium ion accessible oxygen-deficiency quasi-hexagonal tunnels sandwiched between conductive rutile slabs. This unique structure serves to boost redox and intercalation kinetics for extraordinary pseudocapacitive energy storage in hierarchical isomeric vanadium oxides, leading to a high specific capacitance of ~1856 F g–1 (almost sixfold that of the pristine vanadium sesquioxide and dioxide) and a bipolar charge/discharge capability at ultrafast rates in aqueous electrolyte. Symmetric wide voltage window pseudocapacitors of vanadium oxides deliver a power density of ~280Wcm–3 together with an exceptionally high volumetric energy density of ~110mWh cm–3 as well as long-term cycling stability. [ABSTRACT FROM AUTHOR]

Under investigation in this paper is the (2+1)-dimensional Maccari system, which is related to the Kadomtsev-Petviashvili (KP) equation. Bright and dark N-soliton solutions in terms of the Gramian are obtained via the KP hierarchy reduction. Oblique and parallel interactions between the bright solitons and between the dark solitons are studied analytically and graphically. We find that there are elastic and inelastic interactions for the bright solitons, but there are only elastic interactions for the dark solitons. Resonance, breather, attraction and repulsion structures are presented. It is expected that these soliton interactions have potential applications in fluid dynamics, nonlinear optics and plasma physics. [ABSTRACT FROM AUTHOR]

Based on the discrete element method, the three dimensional mixed-size grain/bed collision process has been investigated in this paper. By considering the influence of lateral impact angle on the mean ejection velocity and ejection number, we obtain that the mean lateral ejection velocity increases with the lateral impact angle at large mean diameter cases and also increases with the impact velocity, while decreases with impact angle. The simulation results indicate that although the lateral impact affects the mean ejection velocity, its effect on the mean ejection number is very limited. Moreover, the mean lateral ejection velocity is influenced by the impact angular velocity. Based on these studies, a more comprehensive three dimensional mixed-size splash function is given. It is of great significance to the particle motion based on turbulence in aeolian sand landform. [ABSTRACT FROM AUTHOR]

Water eutrophication has become a worldwide environmental problem in recent years. Once a water body is eutrophicated, it will lose its primary functions and subsequently influence sustainable development of society and economy. Therefore, analysis of eutrophication becomes one of the most essential issues at present. With the ability to deal with vague and uncertain information, and express knowledge in a rule form, the rough set theory (RST) has been widely applied in diverse domains. The advantage of RST is that it can compress the rule and remove needless features by reduction inference rule. By this way, the rule gets effectively simplified and inference efficiency gets improved. However, if data amount is relatively big, it could be a process with large calculated amount to search rules by looking up tables. Petri nets (PNs) possesses so powerful parallel reasoning ability that inference result could be obtained rapidly merely by simple matrix manipulation with no need for searching rules by looking up tables. In this work, an integrated RPN model combining RST with PN was used to analyze relations between degrees of water eutrophication level and influence factors in the Pengxi River of Three Gorges Reservoir. It was shown that the RPN model could analyze water eutrophicaion accurately and quickly, and yield decision rules for the decision-makers at water purification plants of the water quality and assist them in making more cost-effective decisions. [ABSTRACT FROM AUTHOR]

The incipient motion of sand particle from sand bed plays a very important role in the prediction of windblown sand. In this paper, we proposed a new method for predicting the incipient motion of sand particle based on wind speed fluctuation as follows, when the wind speed is larger than the critical wind speed, if the total impulse on sand particle is larger than the critical impulse, incipient motion of sand particle would take place, otherwise if not. Furthermore, from the analysis of entrainment in the rolling and lifting modes, we come to the following conclusion. When the average wind speed is smaller than the critical wind speed, if the average wind speed is used to judge the incipient motion of sand particle, one will underestimate the number of sand particles jumping from the bed, if the instantaneous wind speed is used to judge incipient motion of sand particle, one will overestimate the number of sand particles jumping from the bed; When the average wind speed is larger than the critical wind speed, either the average or the instantaneous wind speeds is used to judge the incipient motion of sand particles, one will overestimate the number of sand particles jumping from the bed. [ABSTRACT FROM AUTHOR]

Three-layer core/shell latex particles with various shell crosslinking level and shell thickness were prepared by multistep emulsion polymerization, and the hollow latex particles with different morphologies were then obtained after alkali post-treatment. Influences of divinyl benzene (DVB) content and the core/shell mass ratio on emulsion polymerization and particle morphology were investigated. Results showed that with the increase of DVB content, the percentage of total amount of -COOH on the particle surface and free in aqueous phase (P SF) decreased, and the morphology of the post-treated particles underwent evolution from cracked, intact hollow to deficient swelling structure. Decreasing the core/shell mass ratio could not only make more carboxyl groups encapsulated by the shell, but also increase the shell resistance to the swelling of the core. The uniform hollow latex particles with intact morphology were obtained when the DVB content was 3.54 wt% and the core/shell mass ratio was 1/6. [ABSTRACT FROM AUTHOR]

The electrification of wind-blown sand has been widely confirmed by field and wind-tunnel measurements. It plays an important role in the lifting and transport of sand particles. In this study we investigated the behavior of electric fields in unsteady saltation by adopting periodic variation wind sequences. The influence of electric fields on sand transport rate was also discussed. The results show that both horizontal and vertical electric fields exist in unsteady saltation, and the transport rate in unsteady saltation is less than that in steady saltation. An interesting result is that the directions of vertical electric field fluctuate upward and downward-pointing with time in the unsteady saltation. This provides a possible explanation for the bipolar pattern of the vertical electric field in wind-blown sand. Graphical abstract: [ABSTRACT FROM AUTHOR]

In order to prepare hollow latex particles with optimum morphology based on osmotic swelling principle, threelayer core/shell latex particles with 40 wt% MAA in the core were first prepared via multistep seeded emulsion copolymerization, in which monomers were added by a semi-continuous process with monomer addition under two different forms: pure monomers’ mixture (monomer addition), and pre-emulsified monomers (pre-emulsion addition). Then, the hollow latex particles with different morphologies were obtained after alkali post-treatment. Influences of the monomer feeding mode on the emulsion polymerization and the particle morphology were investigated. Results showed that the preemulsion addition could significantly improve the polymerization stability in each step, and greatly enhance the uniformity of shell encapsulation. The sizes of the core and core/shell latex particles obtained by the pre-emulsion addition were smaller and more uniform than those synthesized by the monomer addition, and the hollow latex particles with intact morphology were generated by alkali post-treating of the core/shell latexes prepared from the pre-emulsion addition. As the core size increased, the morphology of the post-treated particles underwent evolution from hollow to collapse. Moreover, the mechanism of the particle morphological evolution was proposed. [ABSTRACT FROM AUTHOR]

We investigated the turbulent intensities and Reynolds shear stress at high Reynolds number $$({Re_\tau = 5 \times 10^{6}})$$ in the atmosphere surface layer (ASL) through analyzing observations in near-neutral stratified conditions. The results show that with increasing Reynolds number the streamwise turbulent intensity increases linearly, and the peak of the Reynolds shear stress extends to a higher non-dimensional height, which means that the thickness of the logarithmic region increases. Furthermore, our results provide evidence for treating the ASL as a canonical turbulent boundary layer, the results of which can be extended and applied to higher Reynolds number wall turbulence in the ASL. [ABSTRACT FROM AUTHOR]

In this paper, the probability of the collision behaviors of barchans in aeolian dune fields and the processes of three collision types, i.e., coalescence, breeding and solitary-wave like behavior, are analyzed by the scale-coupled model of dune fields. Moreover, the influence of wind speed, sand diameter, sand supply, the height ratio between two barchans, and the angle between the dune trend and wind direction, as well as the distance between the centerlines of two barchans on the collision results of barchans is demonstrated. [ABSTRACT FROM AUTHOR]

In this paper, the velocities of sand particles near the sand bed in the saltation cloud were measured in a wind tunnel through an improved experimental scheme of the Particle Image Velocimetry (PIV) system. The influences of the diameter of sand particles in the saltation cloud and wind velocity on the probability distribution function (PDF) of lift-off velocities of sand particles were investigated. Results demonstrate that for the sand particles saltating above the sand bed with the mean grain diameter ( d = 0.3 mm), smaller and larger ones have the same velocity distribution, and wind velocity has no obvious influence on the distribution shape of the lift-off velocities, i.e., the PDFs of the horizontal and vertical lift-off velocities both follow a lognormal distribution, but the diameter of sand particles in the saltation cloud and wind velocity have an influence on the parameters of the PDF of horizontal and vertical lift-off velocities. Eventually, we present formulas to describe the PDF of lift-off velocities of sand particles with regard to the influence of wind velocity and the diameter of sand particles in the saltation cloud above the sand bed with d = 0.3 mm. Graphical abstract: [ABSTRACT FROM AUTHOR]

In the research of windblown sand movement, the lift-off and incident velocities of saltating sand particles play a significant role in bridging the spatial and temporal scales from single sand particle's motion to windblown sand flux. In this paper, we achieved wind tunnel measurements of the movement of sand particles near sand bed through improving the wind tunnel experimental scheme of particle image velocimetry (PIV) and data processing method. And then the influence of observation height on the probability distributions of lift-off and incident velocities of sand particles was analyzed. The results demonstrate that the observation height has no obvious influence on the distribution pattern of the lift-off and incident velocities of sand particles, i.e., the probability distribution of horizontal and vertical velocities of lift-off and incident sand particles follow a Gaussian distribution and a negative exponential distribution, respectively. However, it influences the center of the Gaussian distribution, the decay constant and the amplitude of the negative exponential distribution. [ABSTRACT FROM AUTHOR]

A facile method is reported to controllably fabricate one dimensional (1D) polymer nanostructures via metallogel template polymerization. The metallogel was prepared through coordination interactions between silver ions and a ligand (L) bearing three pyridyl groups in tetrahydrofuran (THF). The diameters of the metallogel nanofibers could be tuned by the gel concentration (GC). Due to its high thermal stability and facility of removal, the metallogel was used as the template for radical polymerization of diacryolyl-2,6-diaminopyridine (DADAP) to form poly-diacryolyl-2,6-diaminopyridine (PDADAP) nanostructures. The gradually eroding of the templates by PDADAP provided us an effective way to fabricate various nanostructures of the polymer. We have demonstrated that different 1D nanostructures, including nanoribbons, nanotubes and nanowires, could be selectively fabricated by adjusting polymerization time, monomer concentration and GC. The rheological properties of the gel samples were tested by a rheometer. As prolonging the reaction time, more and more polymers were formed and the strength of the resulting polymer gels became higher and higher. The simple preparation process, easy controlled microstructures and adequate gel strength would make it a facile synthetic method for different 1D polymer nanosturctures. [ABSTRACT FROM AUTHOR]

Soap-free hydrophilic-hydrophobic core-shell latex particles with high carboxyl content in the core of the particles were synthesized via the seeded emulsion polymerization using methyl methacrylate (MMA), butyl acrylate (BA), methacrylic acid (MAA), styrene (St) and ethylene glycol dimethacrylate (EGDMA) as monomers, and the influences of MMA content used in the core preparation on polymerization, particle size and morphology were investigated by transmission electron microscopy, dynamic light scattering and conductometric titration. The results showed that the seeded emulsion polymerization could be carried out smoothly using 'starved monomer feeding process' when MAA content in the core preparation was equal to or less than 24 wt%, and the encapsulating efficiency of the hydrophilic P(MMA-BA-MAA-EGDMA) core with the hydrophobic PSt shell decreased with the increase in MAA content. When an interlayer of P(MMA-MAA-St) with moderate polarity was inserted between the P(MMA-BA-MAA-EGDMA) core and the PSt shell, well designed soap-free hydrophilic-hydrophobic core-shell latex particles with 24 wt% MAA content in the core preparation were obtained. [ABSTRACT FROM AUTHOR]

Poly(maleic anhydride- co-acrylic acid), P(MA-AA), was synthesized by the free-radical copolymerization of maleic anhydride with acrylic acid, and fast responsive pH-sensitive poly(maleic anhydride- co-acrylic acid)/polyethylene glycol, P(MA-AA)/PEG, hydrogels were prepared using PEG as macromolecular cross-linking agent. FT-IR and H-NMR spectrometry were applied to characterize the structure of P(MA-AA). The influences of pH and ionic strength on the swelling behavior of P(MA-AA)/PEG hydrogels and the swelling-deswelling changes along with the repeated changes between acid and alkali conditions were studied. The results showed that there was a hundredfold difference in the swelling ratios between the conditions of acid and alkali, and the swelling capability could not be weakened after multiple swelling-deswelling cycles. The results of swelling kinetics demonstrated that the response rate of P(MA-AA)/PEG hydrogels was very fast, because the swelling transition points always occurred at 10 min. The pH-responsive hydrogels reported here might be a smart material for potentially applications in many areas, including biosensors, drug-delivery devices and tissue engineering. [ABSTRACT FROM AUTHOR]

Coupled modified nonlinear Schrödinger (CMNLS) equations describe the pulse propagation in the picosecond or femtosecond regime of the birefringent optical fibers. A new type of the Lax pair and another hierarchy of the infinitely many conservation laws are derived based on the Wadati-Konno-Ichikawa system. By means of the Hirota method, soliton solutions in the normal dispersion regime are obtained. Parametric regions for the existence of dark and anti-dark vector soliton solutions are given. Asymptotic analysis shows that the collision between two solitons (two anti-dark solitons, two dark solitons, or dark and anti-dark solitons) in each polarization direction is elastic. Moreover, there is no energy transfer between two polarization components of each vector soliton, whether dark or anti-dark vector soliton. In addition, dark and anti-dark solitons can coexist on the same background seen from the collision between the dark and anti-dark solitons in one polarization direction. Our graphical analysis shows that the parameters in the CMNLS equations not only determine the regions for the existence of dark and anti-dark soliton solutions but also control the phase and direction of the propagation of the solitons. Finally, through the linear stability analysis, the modulational instability condition is given. [ABSTRACT FROM AUTHOR]

With the help of symbolic computation, this paper investigates the variable-coefficient Zakharov-Kuznetsov equation which governs the two-dimensional ion-acoustic waves obliquely propagating in an inhomogeneous magnetized two-ion-temperature dusty plasma. The integrability of this model is examined through the Painlevé analysis. Via the Hirota method, the bilinear form of such model is derived. Based on the obtained bilinear form, the N-soliton solution is constructed. Propagation characteristics and interaction behaviors of the solitons are discussed through the graphical analysis. [ABSTRACT FROM AUTHOR]

In this paper, with the computerized symbolic computation, the nonlinearization technique of Lax pairs is applied to find the integrable decompositions for the (2+1)-dimensional Gardner [(2+1)-DG] equation. First, the mono-nonlinearization leads a single Lax pair of the (2+1)-DG equation to a generalized Burgers hierarchy which is linearizable via the Hopf–Cole transformation. Second, by the binary nonlinearization of two symmetry Lax pairs, the (2+1)-DG equation is decomposed into the generalized coupled mixed derivative nonlinear Schrödinger (CMDNLS) system and its third-order extension. Furthermore, the Lax representation and Darboux transformation for the CMDNLS and third-order CMDNLS systems are constructed. Based on the two integrable decompositions, the resonant N-shock-wave solution and an upside-down bell-shaped solitary-wave solution are obtained and the relevant propagation characteristics are discussed through the graphical analysis. [ABSTRACT FROM AUTHOR]

Abstract  Uncoupling protein 1 (UCP1), a 32-kDa protein located in the inner mitochondrial membrane, is abundant in brown adipose tissue, as a proton transporter in mitochondria inner membrane which uncouples oxidative metabolism from ATP synthesis and dissipates energy through the heat. UCP1 has been reported to play important roles for energy homeostasis in rodents and neonate of larger mammals including human. Recently, numerous candidate genes were searched to determine the genetic factors implicated in the pathogenesis of obesity, related metabolic disorders and diabetes. UCP-1, which plays a major role in thermogenesis, was suggested to be one of the candidates. This review summarizes data supporting the existence of brown adipocytes and the role of UCP1 in energy dissipation in adult humans, and the genetic variety association with the fat metabolism, obesity and diabetes. [ABSTRACT FROM AUTHOR]

In this paper, analytically investigated is a higher-order dispersive nonlinear Schrödinger equation. Based on the linear eigenvalue problem associated with this equation, the integrability is identified by admitting an infinite number of conservation laws. By using the Darboux transformation method, the explicit multi-soliton solutions are generated in a recursive manner. The propagation characteristic of solitons and their interactions under the periodic plane wave background are discussed. Finally, the modulational instability of solutions is analyzed in the presence of small perturbation. [ABSTRACT FROM AUTHOR]

Surface films of TiN and TiN/Ti were deposited on Ti6Al4V alloy by arc ion plating (AIP). Open-circuit potential, potentiodynamic polarization tests and electrochemical impedance spectroscopy (EIS) were employed to investigate the corrosion performance of TiN and TiN/Ti films in Hank’s simulated body fluid at 37 °C and pH 7.4. Scanning electron microscopy (SEM) was used to study the surface morphology of the corroded samples after the potentiodynamic polarization tests. The results show that the TiN and the TiN/Ti films can provide effective protection for the Ti6Al4V substrate in Hank’s fluid, and the TiN/Ti composite film showed a corrosion resistance superior to that of the TiN film. The outer TiN layer of the composite film mainly acted as an efficient barrier to corrosion during short-term experiments. In contrast to the bare Ti6Al4V, no pitting was observed on the surface of the TiN and TiN/Ti films deposited on the bare alloy after potentiodynamic polarization. [ABSTRACT FROM AUTHOR]

The phosphatidylinositol-3-kinase-like kinase ATM (ataxia-telangiectasia mutated) has a central role in coordinating DNA damage responses, including cell-cycle checkpoint control, DNA repair and apoptosis. Mutations of ATM cause a spectrum of defects ranging from neurodegeneration to cancer predisposition. However, the mechanism by which DNA damage activates ATM is poorly understood. Here we show that Cdk5 (cyclin-dependent kinase 5), activated by DNA damage, directly phosphorylates ATM at Ser 794 in post-mitotic neurons. Phosphorylation at Ser 794 precedes, and is required for, ATM autophosphorylation at Ser 1981, and activates ATM kinase activity. The Cdk5–ATM signal regulates phosphorylation and function of the ATM targets p53 and H2AX. Interruption of the Cdk5–ATM pathway attenuates DNA-damage-induced neuronal cell cycle re-entry and expression of the p53 targets PUMA and Bax, protecting neurons from death. Thus, activation of Cdk5 by DNA damage serves as a critical signal to initiate the ATM response and regulate ATM-dependent cellular processes. [ABSTRACT FROM AUTHOR]

With the help of symbolic computation, we first derive the bilinear form and an auto-Bäcklund transformation for a perturbed variable-coefficient Korteweg-de Vries equation in this paper. We also construct the N-solitonic solution in the Wronskian form and give the corresponding proof via the Wronskian technique. Furthermore, the authors verify that the ( N−1)- and N-solitonic solutions indeed satisfy the auto-Bäcklund transformation. [ABSTRACT FROM AUTHOR]

Currently, the variable-coefficient nonlinear Schrödinger (NLS)-typed models have attracted considerable attention in such fields as plasma physics, nonlinear optics, arterial mechanics and Bose-Einstein condensates. Motivated by the recent work of Tian et al. [Eur. Phys. J. B 47, 329 (2005)], this paper is devoted to finding all the cases for a more generalized NLS equation with time- and space-dependent coefficients to be mapped onto the standard one. With the computerized symbolic computation, three transformations and relevant constraint conditions on the coefficient functions are obtained, which turn out to be more general than those previously published in the literature. Via these transformations, the Lax pairs are also derived under the corresponding conditions. For physical applications, our transformations provide the feasibility for more currently-important inhomogeneous NLS models to be transformed into the homogeneous one. Applications of those transformations to several example models are illustrated and some soliton-like solutions are also graphically discussed. [ABSTRACT FROM AUTHOR]

Abstract??This paper proposes a new public-key encryption scheme which removes one element from the public-key tuple of the original Cramer-Shoup scheme. As a result, a ciphertext is not a quadruple but a triple at the cost of a strong assumption, the third version of knowledge of exponent assumption (KEA3). Under assumptions of KEA3, a decision Diffie-Hellman (DDH) and a variant of target collision resistance (TCRv), the new scheme is proved secure against indistinguishable adaptive chosen ciphertext attack (IND-CCA2). This scheme is as efficient as Damg?rd ElGamal (DEG) scheme when it makes use of a well-known algorithm for product of exponentiations. The DEG scheme is recently proved IND-CCA1 secure by Bellare and Palacio in ASIACRYPT 2004 under another strong assumption. In addition to our IND-CCA2 secured scheme, we also believe that the security proof procedure itself provides a well insight for ElGamal-based encryption schemes which are secure in real world. [ABSTRACT FROM AUTHOR]

Our previous proteomics study on human hepatocellular carcinoma (HCC) cell strains revealed that cytokeratin 19 (CK19) was expressed in cells with high metastasis potential; we further studied serum CK19 fragment CYFRA 21-1 level in HCC patients and nude mice model of HCC metastasis. HCC cell line HCCLM3 was injected subcutaneously into 30 nude mice which were then randomized into 6 groups of 5 mice each. The murine serum CYFRA 21-1 and pulmonary metastases were determined 2, 3, 4, 5, 6, and 7 weeks after injection. Serum CYFRA 21-1 levels of 101 normal controls and 108 HCC patients were also determined. In nude mice model, CYFRA 21-1 level increased significantly when pulmonary metastases occurred. Among 108 HCC patients, 24 (22.2%) had increased serum CYFRA 21-1 level. The presence of portal vein tumor emboli was significantly higher in CYFRA 21-1 increased cases (33.3%, 6/24) than in CYFRA 21-1 normal cases (6.0%, 5/84) ( x 2 = 7.403, P < 0.01). In addition, the percentage of TNM stage III/IV tumor was significantly higher in CYFRA 21-1 increased patients (54.2%, 13/24) than in CYFRA 21-1 normal cases (21.4%, 18/84) ( x 2 = 9.776, P < 0.005). These results suggest that CK19 may play an important role in HCC metastasis. [ABSTRACT FROM AUTHOR]

The Ostrovsky model is widely used to describe mechanical and physical problems such as internal or surface waves in the oceans and magnetic sounds in plasmas. This model has recently been Grimshaw-regularized for certain continuity in the mass field, while computerized symbolic computation becomes a branch of artificial intelligence. In this paper, some similarity reductions are found for the regularized Ostrovsky-Grimshaw model with symbolic computation, to a coupled set of nonlinear ordinary differential equations. The micropterons and macropterons are analytically presented and discussed, and have been found to contain certain solitonic cores plus a number of sinusoidal ``wings''. Examples are the micropterons and macropterons for fluid velocities in the wave propagation direction and transverse direction, respectively. [ABSTRACT FROM AUTHOR]

Describing space and laboratory plasmas, arterial mechanics and optical fibers, a generalized variable-coefficient nonlinear Schrödinger model is hereby under investigation. Four transformations have been constructed from such a model to the known standard and cylindrical nonlinear Schrödinger equations with the relevant constraints on the variable coefficients presented. Symbolic computation is performed. Specialities of those transformations are discussed. Analytic solutions of such a generalized variable-coefficient model can be obtained via those transformations from the analytic solutions of the standard and cylindrical ones. [ABSTRACT FROM AUTHOR]

Abstract. The Broer–Kaup system is among the important integrable models for the shallow water waves. For a (2+1)-dimensional Broer–Kaup system and with symbolic computation, we present some similarity solutions, which are expressible in terms of the Jacobian elliptic functions and second Painlevé transcendent. Our results are in agreement with the Painlevé conjecture. [ABSTRACT FROM AUTHOR]

Purpose: Cell-matrix adhesive interaction has an important role in the invasive process of tumor cells, and integrins are the major receptors mediating cell-matrix adhesion. The current study is to investigate the modulation of basement membrane (BM) proteins, especially collagen IV (C IV), laminin (LN), and fibronectin (FN) in the invasive processes of human hepatocellular carcinoma (HCC) cells in vitro, and to reveal the roles of β1 integrins and RGD-containing oligopeptide in the cell-matrix interaction. Methods: Static adhesion assay was performed to study the rates of adhesion of MHCC97-H cells, treated or untreated with anti-β1 (2 μg ml-1) and GRGDS, to C IV (50 μg ml-1), LN (50 μg ml-1) or FN (50 μg ml-1). Gelatin zymography was used to detect the secretion of MMPs in the conditioned medium of MHCC97-H cells incubated 24 h by C IV, LN or FN, and interactions with anti-β1 and GRGDS. Transwell chamber assay was used to investigate the influence of C IV, LN or FN, interacting with anti-β1 and GRGDS, on the cellular mobility of MHCC97-H cells. Results: Compared with blank control group, MHCC97-H cells showed significantly higher rates of adhesion to C IV, LN, and FN. Pretreatment with anti-β1 could suppress adhesion to C IV, LN or FN, but GRGDS inhibited adhesion to FN (P<0.05) only. LN and FN could stimulate the secretion of MMPs by MHCC97-H cells cultured in vitro, especially MMP-9 and its activated type. Treatment with anti-β1 could partly counteract the effects of LN and FN. GRGDS could prominently induce the secretion of MMPs, but the effect could be inhibited by pretreatment of anti-β1. The results of Transwell chamber assay showed that LN, FN, and GRGDS could increase the number of tumor cells penetrating the microporous membrane, but the data of C IV did not reach significance. The effects were partly counteracted by anti-β1. Conclusion: BM proteins play an active role in the invasive process of human hepatocellular carcinoma cells. Integrin β1 is an important molecule which mediates the cell-matrix adhesive interaction of tumor cells. RGD-containing peptides competitively combine with the binding site of integrin β1, and the effects of FN are RGD sequence-dependent. [ABSTRACT FROM AUTHOR]

The wave propagation on an ocean or water surface in the presence of sea ice or surface tension is of current importance. In this paper, we investigate the (2 + 1) dimensional 6th-order model proposed recently by Haragus-Courcelle and Il’ichev for such wave propagation. Firstly, we correct some errors in the original derivations of this model. With computerized symbolic computation and truncated Painlevé expansion, we then obtain an auto-Bäcklund transformation and types of the solitonic and other exact analytic solutions to the model, with the solitary waves as a special case, able to be dealt with the powerful Wu method. Based on the results, we later propose some possibly observable effects for the future experiments, and in the end, provide a possible way to explain the regular structure of the open-sea ice break-up observations. [ABSTRACT FROM AUTHOR]

Purpose. To establish a “stepwise metastatic human hepatocellular carcinoma (HCC) cell model system” for in-depth study of the underlying mechanisms of HCC metastasis. Methods. Using MHCC97— a metastatic human hepatocellular carcinoma (HCC) cell line reported in 1999—as the parent cells, we subsequently established three cell lines (MHCC97-L, HMCC97-H, and HCCLM3) with increasing spontaneous metastatic potential. Now, the fourth cell line with unique multiple metastatic characteristics has been established by six rounds of in vivo selection. Results. This cell line, designated as HCCLM6, is a polygonal epithelial cell with hypotriploid karyotype, the modal chromosomes are 55-58, and marker chromosomal abnormalities include i(1) (q10), i(8)(q10), der (4) t(4;8)(q31;q22), i(X)(q10). The cell population doubling time was 32 h. Fluorescent PCR showed HBV DNA integration in the cellular genome. Thirty-five days after HCCLM6 was injected subcutaneously into BALB/c nude mice, prominent lung metastases occurred in 100% of the recipient animals. When tumor tissue was orthotopically implanted into the liver of nude mouse, widespread loco-regional and pulmonary metastases occurred. Inoculation of this cell into the footpad of nude mice also produced 75% regional lymph node metastasis. Compared with MHCC97-L which was not metastastatic via subcutaneous or footpad inoculation and 40% metastatic via orthotopic inoculation, HCCLM6 had increased expression of matrix metalloproteinase (MMP-2 and MMP-9) and cytokeratin 19 (CK19), and decreased expression of Rb2/p130. The establishment of this new cell line has completed our stepwise metastatic HCC cell mode system, which was characterized by a similar genetic background but with significant differences in spontaneous metastasis behavior. Conclusions. The study supports the theory that cancer metastasis is a highly selective dynamic process and the cell model system could be a useful platform for the study of HCC metastasis. [ABSTRACT FROM AUTHOR]

Purpose. To establish stable green fluorescent protein (GFP)-expressing metastatic human hepatocellular carcinoma (HCC) cell lines with different metastatic potential for long-term in vivo studies of metastasis and angiogenesis. Methods. The pIRES2-EGFP vector, which contains an enhanced GFP gene, was transfected into MHCC97-H and MHCC97-L, HCC cell lines with different metastatic potential. The stability of GFP expression, basic biological characteristics, invasion abilities in vitro, and spontaneous metastasis in vivo of the new cell lines (MHCC97-HG and MHCC97-LG) were studied. Microvessel density (MVD) of orthotopic implanted tumors was compared by anti-CD31 immunohistochemical staining, and real-time angiogenesis and metastasis of GFP-transfected tumors were detected by intravital fluorescent microscope. Results. The GFP-transfected cell lines stably expressed green fluorescence in the absence of G418 over a 36-day period. Compared with the parental cell lines, they exhibited no distinct differences in biological characteristics. MHCC97-HG showed more aggressive invasion and spontaneous metastatic behavior than MHCC97-LG, and even its parental cell line, MHCC97-H (P<0.01). MVD levels induced by MHCC97-HG orthotopic implanted tumors were significantly higher than MHCC97-LG (P<0.01). Real-time angiogenesis and sequential steps of metastasis could be detected clearly under intravital fluorescent microscope. Conclusions. These two stable GFP-expressing HCC cell lines with the same genetic background and different metastatic potential were established, which could be useful models for monitoring metastasis and angiogenesis of HCC. [ABSTRACT FROM AUTHOR]

Purpose. The MHCC97 cell line contains two clones with high (MHCC97-H) and low (MHCC97-L) metastatic potentials, for which the pulmonary metastatic rate was 100% vs 40% between the two human hepatocellular carcinoma (HCC) clones. In an effort to elucidate the mechanism of organ-specific metastasis, we studied the effect of lung extracts from C57BL/6 mice on migration and invasion using the MHCC97 cell line. Methods. Determination of migration and invasion induced by lung extracts to MHCC97 cell lines was examined by chemoinvasion assay. The organization of cytoskeleton was tested using filamentous actin (F-actin) polymerization assay and flow cytometry. The activity of matrix metalloproteinase (MMPs) was analyzed by zymogram. Fluorescence double staining was employed for MMPs and F-actin colocalization in MHCC97-H cells induced by lung extracts. Results. The number of cells in response to extracts of lung, liver, kidney, and spleen in MHCC97-H cells was 64±10, 6±2, 22±4, and 3±1, respectively. Of the extracts, lung extracts showed significant differences to promote the migratory and invasive ability for MHCC97-H cells(p<0.001). The number of cells in response to lung extracts was threefold higher in MHCC97-H than that of cells in MHCC97-L (p<0.001). Confocal laser scan microscope of MHCC97-H cells and MHCC97-L cells stimulated with lung extracts revealed pseudopodia formation around the cell front at the indicated time point. With the time increasing, the pseudopodia formation became increasingly more obvious and distinct. Compared with unstimulated cells, analysis of FACS showed a transient 1.9-fold and 1.7-fold increase in F-actin within 30 s in MHCC97-H cells and MHCC97-L cells, respectively. Confocal laser scan microscopy of MHCC97-H cells stimulated in suspension with lung extracts revealed intense F-actin staining in the periphery of the cells and redistribution of F-actin towards a leading edge. After the cells were incubated with lung extracts, not only expressions of active and latent form of MMP-9 were upregulated, but that of latent form of MMP-2 was increased in the MHCC97-H cells and MHCC97-L cells. The levels of latent and active form of MMP-9(18.8±1.2, 100.1±1.1), and latent form of MMP-2(22.4±1.3) were much higher in MHCC97-H cells than those of MHCC97-L cells, which were 7.8±0.3, 40.8±2.2, and 8.2±0.4, respectively. MMP-9 was mainly localized perinuclear pool when the MHCC97-H cells were incubated with serum-free medium. After the cells were stimulated with lung extracts, MMP-9 were expressed and colocalized with F-actin at the front of extending pseudopodia. Conclusions. Our results indicate that the expression of matrix metalloproteinase and the pseudopodia formation in MHCC97-H cells may correlate to the metastatic potential; thus, the host environment may contribute to the preferential metastasis of HCC cells to the lung depending on the high level of MMP-9 and migratory ability. [ABSTRACT FROM AUTHOR]

Presents information on a study which described the gene expression of hepatitis C virus core antigen gene in tobacco plant using a tobacco mosaic virus (TMV)-based vector system. Information on TMV; Materials and methods of the study; Results and discussion.

Describes a natural antibody library constructed using the variable regions from the peripheral blood lymphocytes two donors. Display of human antibody fragments on the surfaces of bacteriophages; Advantages of phage antibody display systems over conventional hybridoma technique in the generation of human antibody; Details on the study.