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Aiming at the problems of long detection time and large detection error when agricultural machinery extracts corn row navigation lines, a method of corn row navigation line extraction based on the adaptive edge detection algorithm is proposed. First, the improved super-green feature algorithm and the maximum inter-class variance method are used to automatically obtain the green feature binary image, and the morphological processing is used to improve the image quality, determining dynamic regions of interest by constraining pixel thresholds, extraction of corn edge contour using adaptive edge detection algorithm, finally, the feature points are fitted by the Theil-Sen estimation method. Experimental results show: the super-green feature algorithm reflects the green content in the image more realistically, using the adaptive edge detection algorithm to extract corn row features, the accuracy rate is 94%, and the processing time of a single frame image is 104ms. Compared with the Hough algorithm extraction and the vertical projection algorithm, the navigation line extraction accuracy is increased by 15% and 8% respectively, and the time-consuming is reduced by 258ms and 150ms respectively. In addition, the stability of the algorithm is analyzed in different environments, all with good timeliness.

An evaporation duct is a type of atmospheric stratification that affects radio systems. Atmospheric duct prediction is helpful for radar detection. In this article, we used the deep forest, which is different from a deep learning framework, to predict the atmospheric duct height. At the same time, the long short-term memory (LSTM) neural network and other machine learning algorithms, such as the logistic regression (LR), random forest (RF), Bayes, and support vector regression (SVR) algorithms, were adopted to predict the evaporation duct height (EDH). The predicted results with filled and unfilled missing data show that an accurate prediction of the EDH can be achieved using the deep forest.

In this study, we use multi‐instrument observations (all‐sky imager (ASI), global navigation satellite system (GPS) receivers, digisonde) to study the interaction of nighttime medium‐scale traveling ionospheric disturbances (MSTIDs) on 13 November 2018. The most attractive aspect of this event is that the interaction appeared between two dark bands both propagated southwestward. The airglow observations show that the latter band moved faster and caught up with the former, and these two bands merged into a new one. The propagating characteristics and morphology of the MSTIDs changed during the interaction process. The simulations from the Thermosphere‐Ionosphere‐Electrodynamics General Circulation Model (TIEGCM) suggested that the ionospheric background zonal winds and electron density distributions could play essential roles in the interaction of the MSTIDs. Moreover, the merging process might be associated with the electrostatic reconnection. This study shows an interesting medium‐scale traveling ionospheric disturbance (MSTID) event. Two MSTID bands encountered during the propagation, the latter dark band caught up with the former band, and then, the two bands merged into one. In contrast, these dark bands kept propagating southwestward. The Thermosphere‐Ionosphere‐Electrodynamics General Circulation Model (TIEGCM) simulations obtain the wind and electron density data, which provide a possible explanation that the changing of ionospheric zonal winds and ionospheric electron density might result in the interaction of these dark bands. Moreover, the merging process might be connected with the electrostatic reconnection, which could be influenced by E×Bplasma flows in opposite directions. Two bands propagated southwestward, the latter band moved faster and caught up with the former, they interacted and merged into oneThe chasing behavior showed the velocity differences, possibly related to the ionospheric zonal wind and electron density distributionThe merging process of the two bands might be connected with electrostatic reconnection Two bands propagated southwestward, the latter band moved faster and caught up with the former, they interacted and merged into one The chasing behavior showed the velocity differences, possibly related to the ionospheric zonal wind and electron density distribution The merging process of the two bands might be connected with electrostatic reconnection

A method for determining optimal reorder point and order quantity (r,Q) inventory control policies is developed. The case where demand increases by units is considered. It was shown that when r is greater than zero, the method requires only (6r + 13Q) elementary operations to determine linear holding and backlogging costs or the amount of work is at most 13 times the amount of work needed for an evaluation of the long-run average cost function in the point (r,Q). However, when r is less than or equal to zero, the number of operations becomes equal to 13Q since only the Q values of the G function are calculated.

Porous metal–organic frameworks (MOFs) have demonstrated a great potential in proton conduction and luminescence sensing due to functionalized nodes, ligands and channels, or pores. Herein, we prepared a hydrothermally stable Eu-MOF that also resisted acid and base using a bifunctional organic ligand containing carboxylic acid groups, which are easily coordinated to Eu ions, and Eu-phobic tetrazolyl groups as potential proton-hopping sites. The hydrogen bond network, which was constructed by the uncoordinated anionic tetrazolium and the coordinated and free water molecules, endowed this Eu-MOF with the highest proton conductivity of 4.45 × 10–2S/cm at 373 K and 93% relative humidity. The proton conductivity of the Nafion membrane containing this Eu-MOF increased 1.74 times. More interestingly, the hybrid membrane displayed luminescence pH sensing because the changeable protonation levels of uncoordinated tetrazolium groups along with the pH tuned the emission of embedded Eu-MOFs. Such a dual-functional MOF-based hybrid membrane including proton conduction and pH sensing is reported for the first time, which could open an avenue to the more practical application for functional MOFs.

Designing high-performance proton-conducting metal–organic frameworks simultaneously having highly hydrothermal stability and a high-density proton carrier remains a great challenge. Fe-MIL-88B is a classic metal–organic framework (MOF) with a large-size one-dimensional (1D) channel lined with a high-density uncoordinated metal atom for postfunctionalization; however this MOF cannot act as a proton conductor due to the weak hydrothermal stability. Here, we prepared an ultrastable isostructure Cr-MIL-88B, which is subsequently functionalized by anchoring 3-pyridinesulfonic acid and 2-(4-pyridyl) ethanesulfonic acid on the naked Cr atoms exposed on the surface of the host-framework, producing two new MOFs, i.e. Cr-MIL-88B-pyridine sulfonic acid (abbreviated as Cr-MIL-88B-PSA) and Cr-MIL-88B-pyridine ethanesulfonic acid (abbreviated as Cr-MIL-88B-PESA). Thus, Cr atoms on the host framework were modified by functional sulfonic groups, which stick out toward the center of the channel forming ordered high-density sulfonic groups as proton donors along the open channel and achieving the highest proton conductivity of 4.50 × 10–2S cm–1for Cr-MIL-88B-PESA and 1.58 × 10–1S cm–1for Cr-MIL-88B-PSA, surpassing that of the Nafion membrane.

Fine modeling and fast prediction of regional wind field in the middle and upper atmosphere has always been a difficult problem. We designed a neural operator method to solve this problem. We combine the idea of data assimilation with deep learning method to design a regional wind field operator suitable for near space. The annual Root mean square error of the zonal wind and meridional wind of the operator model at the height of 30 km are 0.903 and 0.881, respectively, which is three times that of ConvLSTM. Moreover, we validate the sparse spatio‐temporal modeling method of regional wind field operator at 20/30/40/50 km altitude. The result shows that the model is mesh‐free, and can get high‐precision modeling of different spatio‐temporal resolutions, multiple regions and arbitrary positions at one time, which lays an foundation for fine regional modeling and rapid utilization of near space. The complex variation mechanism of regional wind fields in near space leads to the difficulty of high‐precision modeling and fast prediction, which seriously affects the design and flight of near space vehicles. In this study, a regional wind field neural operator method has been proposed, which can achieve the fine modeling of the regional wind field in the middle and upper atmosphere. The new method is highly flexible, and can get high‐precision modeling and rapid prediction in different spatial‐temporal resolutions, multiple regions and arbitrary positions. The neural operator is first used to study high‐precision spatio‐temporal modeling and rapid prediction of regional wind fields in near spaceThe Root mean square error accuracy of regional wind field operator model is three times that of ConvLSTMThe novel method is suitable for sparse spatio‐temporal modeling at any location with different data resolutions The neural operator is first used to study high‐precision spatio‐temporal modeling and rapid prediction of regional wind fields in near space The Root mean square error accuracy of regional wind field operator model is three times that of ConvLSTM The novel method is suitable for sparse spatio‐temporal modeling at any location with different data resolutions

The wind and temperature fields at 20 to 55 km above the Antigua launch site (17°N, 61°W) were analyzed by using sounding rocket data published by the research organization on Stratosphere‐Troposphere Processes and their Role in Climate (SPARC). The results showed distinct variations in the wind and temperature fields at different heights from the 1960s to the 1990s. The overall zonal wind speed showed a significant increasing trend with the year, and the overall change in meridional wind speed showed a falling trend from 1976 to 1990, whereas the temperature field showed a significant cooling trend from 1964 to 1990. The times the trends mutated varied at different levels. By taking the altitudes at 20, 35, and 50 km as representatives, we found that the zonal wind speed trend had mutated in 1988, 1986, and 1986, respectively; that the meridional wind speed trend had mutated in 1990, 1986, and 1990, respectively; and that the temperature trend had mutated separately in 1977, 1973, and 1967, respectively. Characteristics of the periodic wind and temperature field variations at different heights were also analyzed, and obvious differences were found in time scale variations across the different layers. The zonal and meridional wind fields were basically characterized as having a significant periodic variation of 5 years across the three layers, and each level was characterized as having a periodic variation of less than 5 years. Temperature field variation at the three levels was basically characterized as occurring in 10‐year and 5‐year cycles.

A polarization beam splitter (PBS) based on a four-layer slab waveguide is proposed, where a sub-wavelength grating is embedded between the waveguide core and the cladding. This grating not only affords Bragg momentum to tune the propagation constant of guiding modes but also converts the forward zero-order waveguide mode to the backward first one for a specific polarization. Thus, the incident light with polarization that satisfies the phase-matching condition is highly reflected in the waveguide, while other light with orthogonal polarization keeps intact and passes through it efficiently. Numerical simulations show that one can make the compact PBS for both polarizations with an extinction ratio higher than 35 dB, a waveband larger than 80 nm, a grating period tolerance of 20 nm, and a waveguide height tolerance of 80 nm. The revealed mode conversion mechanism via the sub-wavelength grating enriches the design of PBSs for integrated silicon waveguide chips.

Extreme events have become more frequent in the Northern Hemisphere mid‐latitudes in recent decades, hugely impacting the ecosystem and society. The quasi‐resonance amplification (QRA) of planetary waves is considered one of the dynamic mechanisms leading to extreme weather. However, the specific impact of resonant waves caused by QRA on surface heat extremes is still an open issue. Here we show that the QRA of planetary waves leading to heat extremes is closely related to double jets, accompanied by the enhancement of atmospheric blocking and the weakening of planetary wave escaping into the stratosphere. Our results illustrate the important role of mid‐latitude planetary waves with zonal wavenumber m= 6–8 caused by QRA in the increasingly frequent heat waves in recent years, as it can increase the coverage area and occurrence frequency of heat extremes in mid‐latitudes and show a significant impact on preferred regions, especially in Eurasia. In the summer of 2022, the Northern Hemisphere mid‐latitudes were affected by widespread, intense heat waves that developed more quickly than climatologists had expected, hugely impacting the ecosystem and society. Understanding the extent and causes of extreme heat can help local authorities better prepare for the extreme weather that may occur in the near future. Planetary wave, also known as Rossby wave, manifested as a large‐scale oscillation of the midlatitude atmospheric flow, usually forms a snaking shape over the Earth, leading to persistent surface weather systems and often resulting in extreme events. Existing studies have shown that, planetary wave is one of the important dynamic mechanism behind heat waves. At certain frequencies and wavelengths (short‐wavelength), this circumglobal waves disturbance can be significantly amplified through resonance, resulting in heat extremes. Our work indicates that resonant wave plays an increasingly important role in heat events over Northern Hemisphere mid‐latitudes. The long‐term changes in resonant wave trend deserve continuous attention, because an improved understanding of planetary waves behind extreme events can help assess future wave activity's potential social and economic effects. The influence of resonant waves on heat extremes in the Northern Hemisphere mid‐latitude summer is increasing, especially in EurasiThe occurrence of resonant waves is closely related to double jets, accompanied by the enhancement of atmospheric blockingThe occurrence of resonant waves is accompanied by the weakening of the upward‐propagating planetary waves The influence of resonant waves on heat extremes in the Northern Hemisphere mid‐latitude summer is increasing, especially in Eurasi The occurrence of resonant waves is closely related to double jets, accompanied by the enhancement of atmospheric blocking The occurrence of resonant waves is accompanied by the weakening of the upward‐propagating planetary waves

The statistical characteristics of inertia‐gravity waves (IGWs) in the troposphere (2–14 km) and lower stratosphere (18–28 km) are analyzed using daily radiosonde observations over six stations in the Western Pacific from 2013 to 2018. Stokes parameter method is used to extract the characteristic parameters of gravity waves (GWs), which are divided into upward and downward propagating waves, and compared with the results of hodograph analysis. In the stratosphere, due to the filtering effect of the background wind field, the IGWs generated in the troposphere mainly propagate eastward with lower frequency range. The tropospheric IGWs have obvious seasonal variation in spectral amplitude and energy, with the maximum in winter and the minimum in monsoon from 2013 to 2018. The stratospheric IGWs are enhanced during phase transition of the quasi‐biennial oscillation, when the enhanced easterly wind appears in the lowest stratosphere, accompanied by enhanced wave energy in the troposphere. During the quasi‐biennial oscillation disruption in late 2015 and early 2016, the tropospheric wave source excites more intense IGWs propagating upward. After reaching the stratosphere, IGWs with slower phase speed are absorbed by the mean flow, dissipating momentum to the lower stratosphere and generating additional enhanced westward forcing, which may have contributed to the development of the easterly wind within the westerly quasi‐biannual oscillation phase. Stokes parameter method shows an obvious discrepancy from hodograph analysis when calculating the vertical wave numberOver the western Pacific, a large amount of eastward‐propagating inertia‐gravity waves (IGWs) still exist in the stratosphere due to prevailing easterly windDuring 15/16D, stratospheric IGWs with lower phase velocity dissipate momentum and produce westward forcing to the mean flow Stokes parameter method shows an obvious discrepancy from hodograph analysis when calculating the vertical wave number Over the western Pacific, a large amount of eastward‐propagating inertia‐gravity waves (IGWs) still exist in the stratosphere due to prevailing easterly wind During 15/16D, stratospheric IGWs with lower phase velocity dissipate momentum and produce westward forcing to the mean flow

Propagation of ultrashort intense laser pulses in a plasma Bragg grating induced by two intersecting laser pulses is studied. Such a plasma grating exhibits an ultrawide photonic bandgap, near which the strong dispersion appears. Particle-in-cell (PIC) simulations show the light speed reduction, pulse stretching, chirped pulse compression, and fast compression of Bragg grating solitons in the plasma grating. The nonlinear coupled-mode theory agrees well with the PIC results. Since the plasma grating can support an ultrahigh damage threshold, it can be a novel photonic device to manipulate extremely intense femtosecond laser pulses.

Isomers of evodiamine derivatives 2and 3were obtained by straightforward asymmetric total synthesis and their antitumor activity was investigated. All the four isomers exhibited good to excellent antitumor potency.

There is a huge demand to develop a method for marine search and rescue (SAR) operators automatically predicting the most probable searching area of the drifting object. This paper presents a novel drifting prediction model to improve the accuracy of the drifting trajectory computation of the sea-surface objects. First, a new drifting kinetic model based on the geometry characteristics of the objects is proposed that involves the effects of the object shape and stochastic motion features in addition to the traditional factors of wind and currents. Then, a computer simulation-based method is employed to analyze the stochastic motion features of the drifting objects, which is applied to estimate the uncertainty parameters of the stochastic factors of the drifting objects. Finally, the accuracy of the model is evaluated by comparison with the flume experimental results. It is shown that the proposed method can be used for various shape objects in the drifting trajectory prediction and the maritime search and rescue decision-making system.

There is a huge demand to develop a method for marine search and rescue (SAR) operators automatically predicting the most probable searching area of the drifting object. This paper presents a novel drifting prediction model to improve the accuracy of the drifting trajectory computation of the sea-surface objects. First, a new drifting kinetic model based on the geometry characteristics of the objects is proposed that involves the effects of the object shape and stochastic motion features in addition to the traditional factors of wind and currents. Then, a computer simulation-based method is employed to analyze the stochastic motion features of the drifting objects, which is applied to estimate the uncertainty parameters of the stochastic factors of the drifting objects. Finally, the accuracy of the model is evaluated by comparison with the flume experimental results. It is shown that the proposed method can be used for various shape objects in the drifting trajectory prediction and the maritime search and rescue decision-making system.

In this paper a speed tracking controller is designed for Permanent Magnet Synchronous Motor (PMSM) integrated starter generator (ISG) operation in the starter based on adaptive backstepping technique. The PMSM drive system is often faced with some parameter variations and unknown disturbances. The designed controller can make the internal combustion engine (ICE) reach ignition speed quickly and meet the torque small pulsating and speed goes smoothly requirements. Then establish the controller model and simulate the ISG operation in the starter. Some simulation results verify the feasibility and illustrate the performance of the controller under the various conditions.

Since fully automatic image segmentation on natural images is usually hard to provide guaranteed results, interactive scheme with a few simple user inputs becomes a good alternative. This paper presents a novel interactive method based on regional attacking and merging mechanism within a cellular automaton (CA) framework. With an attacking rule based on regions maximal similarity, the adjacent homogeneous regions that are initialized by pre-segmentation are automatically merged and labeled, the users only need to indicate the object and background regions with rough markers. The whole process neednt set any similarity threshold in advance and the desired contours are effectively extracted by labeling all the non-marker regions as either background or object. Extensive experiments are performed and the results show that the proposed scheme can reliably extract the object contours from the complex background.

Level set method is convenient in image segmentation for the stabilization and veracity. Gaussian filter is usually taken as a preprocess to reduce the influence of weak edges due to noises, but the disadvantage is obvious: blur fine structures specially the important boundaries and lead to inaccurate segmentation result. This paper introduces a robust method which filters the images with a Nonlinear Coherent Diffusion (NCD) to accelerate the evolution of level set in a spatially varying manner. Experimental results show the performance of the proposed method in improving precision of segmentation.

Endoscopic biliary stent placement during the procedure of endoscopic retrograde cholangiopancreatography (ERCP) is preferred to provide biliary drainage for unresectable malignant biliary obstruction. There is considerable controversy over the use of endoscopic sphincterotomy (ES) prior to stent placement. This study aimed to determine whether ES before intraductal self-expanding metal stent (SEMS) placement affects the clinical outcome and complications in patients with proximal malignant obstructive biliary diseases.

Noting that in traditional study, the dynamic response of the tower structure under wind load is usually analyzed by explicitly applying equivalent force on nodes of the tower’s finite element model which may oversimplify the flow-structure interaction interface, this paper presents a fully coupled finite element study of the dynamic response of monopole steel tower. Coupled finite element analysis is used to model the interaction between the steel tower and the wind flow. The steel tower is composed of tubes and is modeled using solid element, while the wind flow is governed by Navier-Stokes equations for incompressive flow. Parameters such as the viscosity of the flow and boundary conditions (wind velocity at different height) are measured from experiments. At each time step of the calculation, winslow moving mesh is used to rezone the computational grid to ensure the accuracy. Simulation is given for studying the deformation pattern of the tower structure.

Terahertz (THz) signals measured by means of the spectral-encoding technique with different temporal discrepancies between probe pulses and THz signals are investigated. It is found that imperfect synchronization between the chirped probe and THz pulses induce a distortion and this distortion affects significantly the retrieved THz spectrum if the temporal discrepancy is large. The distortion becomes more prominent if the probe pulse length is less than the optimal chirped probe pulse duration. A simple approach is proposed to realize the synchronization and minimize the distortion. THz signals from a high-voltage-biased air plasma filament are measured with this approach and distortion similar to the simulation results is observed.

A method for analyzing wind-induced vibration and its control of transmission tower-line system in mountainous area is described. The method is applied to a real transmission line containing two self-supporting steel angle towers, 3 spans of conductors and ground lines together with insulators. Analyses are conducted for the out-of-plane wind direction, and the fluctuating wind load on tower-line system is simulated by harmony superposition method and davenport spectrum. The numerical results indicate that the wind-induced response and its control effect are mainly related to the stiffness of the towers, rather than the mounting height or the spans of the power lines. At the same time, viscoelastic dampers fixed on the main members can suppress the wind-induced displacement of the towers effectively.

With the rapid development of tourism in“3+5” urban agglomeration, more and more attention is paid to ecological security triggered by tourism wave. Taking Loudi City in urban agglomeration as an example, conduct empirical study on the application of ecological footprint theories and methods on the quantitative evaluation of sustainable development of regional tourism. The results show: tourism ecological footprint per capita of Loudi was 768.9881×10-5hm2 in 2009 in which transportation taking 55.3156% is the maximum, and food consumption taking 39.7622% is the second one. Tourism ecological capacity per capita was 1520.5170×10-5hm2; tourism ecological surplus per capita was 751.5289×10-5hm2 and ecological security degree was 0.5057 which showed a common condition or could be said as a safer condition. However, with the rapid development of tourism, tourism ecological footprint of Loudi City shows an increasing trend year by year. We should coordinate well the relationship between tourism development and ecological environmental protection.

Objectives To valuate the prognostic impact of hydronephrosis in bladder cancer treated by radical cystectomy.Methods We performed a retrospective review of 126 patients with transitional cell carcinoma of bladder, who underwent radical cystectomy at our hospital from January 2003 through May 2010. The relationship between hydronephrosis, tumor stage, and lymph node status was analyzed. We evaluated the effect of hydronephrosis on the recurrence-free survival of bladder cancer by using log-rank test and multivariate Cox regression analysis.Results Thirty-four patients had unilateral hydronephrosis and five patients had bilateral hydronephrosis. There were 59.0% of tumors with stage ≥pT3a, and 30.8% with pT2, 10.2% with pT1 in the Hydronephrosis group respectively compared to 14.9%, 59.8%, and 25.3% in the Non-hydronephrosis group (ΧcH2= 25.680, P<0.001). The 5-year recurrence-free survival rates in the Hydronephrosis group were significantly lower than the Non-hydronephrosis group (42.5±10.3% vs. 68.8±8.1%, P=0.001). When adjusted to the different stages stratum, the recurrence-free survival rates among patients with stage pT1–2pN- or lymph node metastasis did not differ significantly whether they had evidence of preoperative hydronephrosis or not, while they differed significantly in the subgroup of stage ≥pT3a, pN-. Multivariate analysis showed that hydronephrosis was not an independent prognostic factor for recurrence-free survival except pathological stage and lymph node status.Conclusions Preoperative hydronephrosis predicts advanced stages in transitional cell carcinoma of bladder and exactly effects the survival mainly in higher stage tumor without metastasis.

Abstract: This paper presents a novel method for assisting surgeons in automatically computing an optimal surgical plan by directly specifying the desired correction to a facial outline. First, the desired facial appearance is designed using a 3D sculpturing tool, while the cut regions of the skull are defined based on facial anatomy. Then, the deformation of the face meshes is performed using an improved biomechanical model in which virtual external forces are driven by the displacements corresponding to the differences of node coordinates between the original and specified face meshes, and free nodes and fixed nodes are defined in terms of the contact surfaces between the soft tissues and the bones within the cut regions. Finally, the shape of the contact surfaces is updated following the deformation of the soft tissues. After registering the deformable contact surfaces and the cut surfaces, the final positions of the cut bones are estimated. Evaluation of preliminary experimental results quantitatively shows the effectiveness of the proposed approach.

Plasma Bragg density gratings produced by optical-field ionization in underdense gas under the irradiation of two counterpropagating laser pulses at laser intensities around 10^13 W/cm^2 are investigated by particle-in-cell simulation. The grating is composed of interlacing layers of neutral gas and plasma (or partially ionized gas) with its density and period controlled by the initial gas density, laser wavelengths, and intersecting angles of the two laser pulses. The study shows that such gratings have a longer lifetime, about nanoseconds, as compared with those driven by the laser ponderomotive force at higher laser intensities around 10^15 W/cm^2. They may be used for phase-matched high-harmonic generation, laser self-guiding, laser pulse compression and stretching, etc.

In the two-dimensional simulation of the interaction of an ultrashort intense laser with droplet plasma, two hot electron jets generated by resonance absorption and emitted symmetrically with respect to the laser propagation direction are observed at a low laser field amplitude such as $a_0=0.1$. However, the emission angle of electron jets cannot be explained simply with the theory of resonance absorption for planar targets. When the laser amplitude is increased to $a_0=2$, electron bunches generated by the ponderomotive force separated by a laser period are superimposed into the hot electron jets. Accelerated ions have two groups at low laser intensities, one is anisotropic and associated with hot electron jets and the other is isotropic due to hydrodynamics expansion. At high light intensities, isotropic ion acceleration is found through Coulomb explosion.

Versican is a large chondroitin sulfate proteoglycan belonging to the lectican family. Alternative splicing of versican generates at least four isoforms named V0, V1, V2, and V3. We have shown that the versican V1 isoform not only enhanced cell proliferation, but also modulated cell cycle progression and protected the cells from apoptosis. Futhermore, the V1 isoform was able to not only activate proto-oncogene EGFR expression and modulate its downstream signaling pathway, but also induce p27 degradation and enhance CDK2 kinase activity. As well, the V1 isoform down-regulated the expression of the proapoptotic protein Bad. By contrast, the V2 isoform exhibited opposite biological activities by inhibiting cell proliferation and down-regulated the expression of EGFR and cyclin A. Furthermore, V2 did not contribute apoptotic resistance to the cells. In light of these results, we are reporting opposite functions for the two versican isoforms whose expression is differentially regulated. Our studies suggest that the roles of these two isoforms are associated with the subdomains CSbeta and CSalpha, respectively. These results were confirmed by silencing the expression of versican V1 with small interfering RNA (siRNA), which abolished V1-enhanced cell proliferation and V1-induced reduction of apoptosis.

AbstractThe first demonstration of laser action in ruby was made in 1960 by T. H. Maiman of Hughes Research Laboratories, USA. Many laboratories worldwide began the search for lasers using different materials, operating at different wavelengths. In the UK, academia, industry and the central laboratories took up the challenge from the earliest days to develop these systems for a broad range of applications. This historical review looks at the contribution the UK has made to the advancement of the technology, the development of systems and components and their exploitation over the last 60 years.

The characteristics of gravity wave activity in tropical areas have been extensively explored, but at present, less attention has been paid to the activity of inertial gravity waves (IGWs) in the Western Pacific based on in‐situ detection data. Based on the radiosonde data over Guam (13.3°N, 144.4°E) for 6 years (2013–2018), the hodograph method and spectrum analysis are used to analyze the statistical characteristics of IGWs in the troposphere (2–14 km) and stratosphere (18–28 km). The gravity wave (GW) energy in the troposphere has clear annual cycle, with the strongest activity in winter and the weakest in monsoon. In the stratosphere, the periodic variation of wave energy is interrupted due to the 2016 quasi‐biennial oscillation (QBO) disruption reflected in the zonal wind field. In the troposphere, the quantity of up‐propagating GWs is close to that of the down‐propagating GWs, while in the stratosphere, they are almost up‐propagating GWs. The horizontal propagation direction of GWs is mainly northeast and southwest in both the troposphere and the stratosphere, since the weak background wind field does not produce significant filtering effect. The spectral amplitude based on the normalized temperature perturbation has clear uniform annual variations in the troposphere and stratosphere, which are the largest in winter and the smallest in monsoon. Due to the “saturation” process in the up‐propagating process of GWs, the spectral slope is more negative in the stratosphere. Detailed parameters of inertial gravity waves revealed in the radiosonde data at Guam Station are discussedGravity wave activity in the stratosphere has obvious 2016 quasi‐biennial oscillation (QBO) disruption, which is consistent with the zonal wind fieldThe result is compared with Gadanki at the same latitude, showing some regional differences Detailed parameters of inertial gravity waves revealed in the radiosonde data at Guam Station are discussed Gravity wave activity in the stratosphere has obvious 2016 quasi‐biennial oscillation (QBO) disruption, which is consistent with the zonal wind field The result is compared with Gadanki at the same latitude, showing some regional differences

Timing of vegetal-endodermal cell determination in amphioxus embryos remains uncertain. We tentatively tested effects of A23187, the calcium ionophore, on the development of vegetal blastomeres isolated at the 16-cell stage. It was found that when vegetal blastomeres committed to endoderm were treated with A23187 prior to gastrulation, they were transformed into ectodermal cells as evidenced by the cell morphology and function characteristic of epidermis. However, the developmental fate of the same blastomeres untreated or treated with DMSO at the same stage or of those treated with A23187 after gastrulation remained unchanged. Thus, vegetal-endodermal cells in amphioxus embryos are not irreversibly determined before the gastrula stage, and artificial increase in intracelluar Ca2+concentration can induce transdetermination of the predetermined endodermal cells into ectodermal cells.

The frequency shift and the pulse compression of an ultrashort laser pulse propagating in a background plasma wave are unified in the concept of phase modulation of the laser pulse by the plasma wave. An equation for the evolution of the pulse width is obtained, which is analogous to the energy-conservation equation for a classical particle moving in a potential well. The threshold amplitude of the plasma wave for pulse compression is estimated. Numerical calculations are presented to confirm these results. Laser pulse compression by a plasma wave should be feasible.

The band transport model is used to derive the space-charge field induced by an optical beam propagating in photorefractive materials with the application of an external dc field in the steady state. The derivation explicitly displays the screening and diffusion fields and other higher-order corrections to them. The condition caused by the screening field for steady-state self-trapping of the optical beam is found analytically by means of a variational approach and compared with the numerical solution. The deflection of the optical beam that is caused by the asymmetric diffusion field, as well as its effect on self-trapping, are also studied.

Abstract: Based on the nonlinear characters of the discrete problems of some elliptical variational inequalities, this paper presents a numerical iterative method, the schemes of which are pithy and converge rapidly. The new method possesses a high efficiency in solving such applied engineering problems as obstacle problems and free boundary problems arising in fluid lubrications.

Supercontinuum generation in air using tightly focused femtosecond laser pulses was investigated experimentally. Broadband white-light emission covering the whole visible spectral region was generated. Spectral broadening extended only to the blue side of the fundamental frequency due to the phase modulation induced by the strong ionization of air. Numerical simulation was also performed to confirm the spectral broadening mechanism. A constant UV cutoff wavelength close to 400?nm was observed in the supercontinuum spectrum. This phenomenon indicated that intensity clamping still plays a role in tight focusing geometry.

It is shown by simulations that terahertz (THz) radiation can be produced more efficiently by a mid-infrared laser pulse from a gas target. The THz amplitude is enhanced by 35 times as the laser wavelength increases from 1 μm to 4 μm; a 4 μm laser at 10^15 W cm^−2 produces 5 MV/cm THz radiation. The THz amplitude changes oscillatingly with increasing laser intensity for a given laser wavelength. In addition, the laser intensity threshold for the THz emission is lower for a longer laser wavelength.

Based on the round‐trip intelligent sounding system, the structure function and spectrum analysis method were carried out to analyze the scale interactions between the small‐scale gravity wave and turbulence in the middle stratosphere. The result showed that the generation of turbulence was closely related to the Kelvin‐Helmholtz (KH) billows. An upscale energy cascade occurred on the spatial scale of KH billows, while a downscale energy cascade occurred on a larger spatial scale (gravity wave scale), which resulted in the breaking of the gravity wave and generation of turbulence. From the multilevel signal measurement, the obvious interactions between turbulence and gravity can be found. The two‐dimensional turbulence that the inverse energy cascade in 2‐D exists simultaneously with a direct enstrophy cascade to the small scales was found, which is considered to be the first‐hand observation result of relevant height. The two‐dimensional turbulence is found with bidirectional energy transmissionKH billows are considered to be an important factor in the excitation of turbulenceConvergence and divergence on different scales cause instability within the wave

Three-dimensional particle-in-cell simulations of the interaction of an ultra-intense linearly-polarized laser light with an overdense plasma are presented. Intense laser radiation is shown to be unstable against modulation both in the direction of the laser propagation direction and in the direction perpendicular to the polarization direction. Growth rate of the instability has a maximum when laser frequency is of the order of the plasma frequency modified due to the relativistic increase of electron mass in the laser field. Analytical description of the instability is also presented.

This is a reply to the comment by Chung and Chung [J. Phys. A27(1994) 5037]. We point out that the discussion there is imperfect.

The Z → e+e- decay is studied based on the noncommutative standard model with the hybrid gauge transformation. It is shown that if the latter is not included, the noncommutative correction to the amplitude of the Z → e+e- appears only as a phase factor, so that there is no new physical effect on the decay width. However, when the hybrid gauge transformation is included, the noncommutative effect appears in the two-body decay process. The discrepancy between the experimental branch ratio and the standard model prediction allows us to set the bound on the noncommutative parameters. [ABSTRACT FROM AUTHOR]