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We report the magnon-dragged magnetoresistance and spin Seebeck effect simultaneously in lateral yttrium iron garnet (YIG)/Ir20Mn80 thin films, which are detected as $R_{{\text {drag}}}$ and $R_{{\text {SSE}}}$ , respectively, namely, the nonlocal inverse spin Hall voltages quantified by the injected current. According to their different dependences on applied current, $R_{{\text {drag}}}$ and $R_{{\text {SSE}}}$ can be separated as the antisymmetric and symmetric part of the nonlocal signals. By a simple magnon diffusion model, the diffusion length of electrically generated magnons is calculated which is comparable to the values reported in YIG/Pt structures. The low magnetic field and the temperature dependences of $R_{{\text {drag}}}$ and $R_{{\text {SSE}}}$ are found to be different, indicating that the origin and transport properties of magnons associated with these two effects are distinct. [ABSTRACT FROM AUTHOR]

The interaction between the joints and the rock bridge beforehand is very complex, which is mainly reflected in the sequence of mobilization and stress distribution between them. To better understand the influence of the rock bridge, direct shear tests were carried out through a newly proposed method on rock specimens which contain two parallel incipient joints. As an innovative study, a method of preparing specimens using 3D printing technology is presented and the localized deformation in rock bridge and joint area is of interest. Test results showed that the failure process of nonpersistent closed rough joints can be divided into seven stages. The seven stages have been successfully verified using PFC2D (Particle Flow Code 2D). The joint surface roughness influences the mobilization pattern by altering the failure process, while rock bridges can weaken the transmission of shear stress, causing the mobilization displacements of the joints on either side of the rock bridge to be out of sync. The roughness of the joint surface after shearing increases with increasing initial JRC. The rock bridge reduces the peak displacement of the joint surface by altering the degree of wear of the joint surface; and the peak displacement of the rock bridge increases due to the unsynchronised mobilization of the joint surface on either side of the rock bridge, thus altering the failure behavior of the rock joints. Highlights: By analyzing the localized deformation of a rock bridge and joint surfaces, the interaction between them and the shear failure characteristics of the whole joint plane were investigated. Rock bridge in nonpersistent joints weakens the transmission of shear stress, causing the mobilization displacements of the joints on either side of the rock bridge to be out of sync. The peak displacement of the rock bridge increases due to the unsynchronized mobilization of the joint surface on either side of the rock bridge, thus altering the failure behavior. [ABSTRACT FROM AUTHOR]

Stand-off laser-induced breakdown spectroscopy (ST-LIBS) has developed into an excellent technology for remote analysis of geological samples. In this study, the rock classification capability of principal component analysis (PCA) was illustrated. The method of automatic spectral peaks identification with linear discriminant analysis (ASPI-LDA) was first applied for classification of rocks and compared with manual spectral peaks identification with linear discriminant analysis (MSPI-LDA). The spectra of rocks were obtained using Echelle and Czerny–Turner spectrometers at 5 m distance and the spectrum peaks were automatically and rapidly identified with ASPI-LDA, not manually identified one by one. The results suggested that MSPI-LDA outperformed PCA in classification performance and, the predictive classification accuracies were further significantly improved by ASPI-LDA with two spectrometers. Besides, the performances of two spectrometers were compared. The results showed that the ASPI-LDA algorithm remedied for the weakness of a compact Czerny–Turner spectrometer having a narrow spectral range to achieve high accuracy classification. Meanwhile, the compact spectrometer used for field detection in ST-LIBS was miniaturized and of lower cost. This indicates that ASPI-LDA combined with a compact spectrometer has a great potential for field in situ remote detection in ST-LIBS. [ABSTRACT FROM AUTHOR]

Stand-off laser-induced breakdown spectroscopy (ST-LIBS) has attracted increasing attention as a valuable method for the remote analysis of materials. In this work, a multi-collector (MC) system combining low cost small lenses imitating the structure and shape of an artificial optical compound eye (AOCE) is presented to enhance the spectral intensity of ST-LIBS. The volume of the MC system is one eighteenth smaller than that of a telescope system and the number of collectors can be flexibly changed according to the requirements. The mechanisms of spectral enhancement are also discussed. In order to illustrate the performance of the MC system, the spectral intensities and the limits of detection (LoDs) of Mn and Cr elements acquired by the telescope system and the MC system were compared at a distance of 2 meters. The results showed that the spectral intensity acquired from the MC system was enhanced by 2.2 times, and the LoDs of Mn and Cr were decreased to 294 μg g−1 and 49 μg g−1. These results indicate that the MC system has great potential in providing a portable, flexible and effective collection method for remote detection. [ABSTRACT FROM AUTHOR]

Due to the complex geometric distribution of discontinuities, the determination of the shear strength of rock masses has become a difficult task limiting the stability analysis of surrounding rock masses in underground tunnels. This problem might be attributed not only to the size effect of fractured rock masses but also due to the difficult quantification of the geometric distribution of fracture systems. To find a solution to this problem, a series of direct shear tests were numerically simulated by utilizing the synthetic rock mass method (SRM) in the PFC3D software to estimate the shear strength of a rock mass in Qingdao Metro tunnels, located in Shandong province, China. The numerical simulation results show that the shear strength parameters vary significantly with the orientation of the fracture network contained in the rock mass. Meanwhile, it was found that the fracture tensor component in the direction z, Fzz, which is in the perpendicular direction to the shearing plane (x–y plane) of the rock mass displayed an inversely varying trend with the shear strength parameters. Accordingly, a shear strength model was established for the rock mass by introducing Fzz to reflect the effect of the geometric distribution of the complex fracture system. The developed shear strength model was verified by conducting direct shear tests in the field, and a good agreement has been achieved. [ABSTRACT FROM AUTHOR]

Background Cholecystokinin ( CCK), a gut hormone that is released during feeding, exerts gastrointestinal effects in part through vagal pathway. It is reported to be a potential trigger for increased postprandial visceral sensitivity in healthy subjects and, especially in patients with irritable bowel syndrome. NR2B-containing N-methyl- d-aspartate ( NMDA) receptors in the central amygdala (CeA) participate in pain modulation. Systemically administered CCK activates the CeA-innervating neurons. Here, we investigated whether CCK modulation of visceral sensitivity is mediated through CeA NMDA- NR2B receptors and whether this modulation involves vagal pathway. Methods We first examined the visceromotor response ( VMR) to colorectal distention ( CRD) following i.p. injection of CCK octapeptide ( CCK-8) in a rat model. Next, the NR2B antagonist ifenprodil and the NR2A antagonist NVP- AAM077 were microinjected into the CeA before systemic CCK injection. NR2B phosphorylation was detected by Western blot. To down-regulate NR2B gene expression, NR2B-specific small interfering RNA (si RNA) was delivered into CeA neurons by electroporation. In addition, the effects of functional deafferentation by perivagal application of capsaicin and pretreatment with the CCK1 receptor antagonist devazepide were investigated. Key Results CCK-8 increased VMR to CRD in a dose-dependent manner. This effect was blunted by intra-CeA administration of ifenprodil (but not NVP- AAM077) and was accompanied by phosphorylation of NR2B subunits in the CeA. CCK failed to increase VMR to CRD in NR2B si RNA-treated rats. Perivagal capsaicin application and pretreatment with devazepide prevented CCK-induced pronociception and CeA NR2B phosphorylation. Conclusions & Inferences The pronociception induced by systemic CCK, which is vagal afferent-dependent, requires activation of CeA NMDA- NR2B receptors. [ABSTRACT FROM AUTHOR]

Aberrant DNA methylation of promoter region CpG islands may serve as an alternative mechanism to genetic defects in the inactivation of tumor suppressor genes ( TSGs) in human malignancies. The aim of this study was to examine the promoter methylation status of the PTEN TSG and its association with esophageal squamous cell carcinoma ( ESCC) carcinogenesis in a Chinese Kazakh population, which is known to have a relatively high ESCC incidence and mortality. The methylation status of the PTEN promoter region was determined in patients with ESCC ( n = 95) and healthy individuals ( n = 65) using highly sensitive Sequenom Epityper assays. The methylation level of the PTEN gene was significantly higher in patients with ESCC than in healthy controls. The median methylation level was 10.0% (interquartile range [ IQR]: 7.0-11.0%) in patients with ESCC and 6.0% in controls ( IQR: 4.0-9.0%; P = 0.001). PTEN methylation levels were higher in male patients with ESCC than in male controls, whereas a trend toward significance was observed between female patients with ESCC and female controls ( P = 0.005 and P = 0.086, respectively). The PTEN methylation level was associated with histopathological grade and lymph node metastasis in patients with ESCC ( P = 0.002 and P = 0.009, respectively). To our knowledge, this is the first report to show the presence of PTEN promoter CpG hypermethylation in ESCC and its association with tumor metastasis. [ABSTRACT FROM AUTHOR]

A planar ultra-wideband monopole antenna with multiple notched bands characteristics is presented. The antenna satisfies the VSWR requirement of less than 2.0 in the frequency band between 2.84 and 12 GHz, except four frequency stop-bands of 3.2-4.1 GHz, 5.0-5.4 GHz, 5.79-6.07 GHz and 6.6-7.8 GHz. By employing a hook-shaped defected ground structure (DGS) in each side of the ground plane, embedding an Sl-shaped slot on the radiating patch, adding a semi-octagon-shaped resonant ring on the back side of the antenna and etching a u-shaped slots beneath the feedline, multiple notched frequency bands are achieved. The antenna shows fairly stable radiation pattern, good group delay and transmission characteristics over the frequency range of interest. The fidelity (F) and the time window containing 90% of the transmitted energy (RE90) are resorted to estimate the time domain characteristics of the proposed antenna. [ABSTRACT FROM AUTHOR]

A novel method for the synthesis of cross-coupled filters through optimization is presented. Based on the relationship between zeros and poles of the characteristic function, an improved error function is proposed, which may increase the optimization algorithm efficiency and precision. Moreover, the full-wave EM simulation is used to find the relationship between the desired parameters and physical structure of the filter. Furthermore, a microstrip filter example is employed to illustrate the procedure and validity of the proposed method. [ABSTRACT FROM AUTHOR]

Novel dual band-notched monopole antenna is proposed in this paper, which is designed by an improved particle swarm optimization algorithm linked with HFSS. By etching a one order Minkowski fractal slot on the radiating patch and introducing a semi-octagon-shaped resonator on the back plane, excellent dual notched frequency bands characteristics of the proposed antenna are achieved. The antenna satisfies the VSWR requirement of less than 2.0 in the frequency band between 2.87 and 12 GHz, except two frequency stop-bands of 3.2–4.01 GHz and 5.55–6.1 GHz. The effects of the key parameters on the dual notched bands are also analyzed. A fairly stable radiation pattern over the frequency range of interest can be obtained. Moreover, measured group delay and transmission characteristics indicate that the antenna has good pulse handling capabilities. [ABSTRACT FROM AUTHOR]

This paper is concerned with the diffusive Nicholson’s blowflies model with nonlocal (or spatiotemporal) delay. When the spatial variable is one-dimensional, we establish the existence of travelling wave-front solutions by using the approach developed by Wang, Li, and Ruan (J. Differ. Equ. 222, 185–232, 2006) on the existence of travelling front solutions of reaction–diffusion systems with nonlocal delay. Moreover, we consider the dependence of the minimal wave speed on the delay and the mobility of the population. Our main finding here is that delay can induce slow travelling wave-fronts and the mobility of the population can increase fast travelling wave-fronts. In particular, if we choose some special kernel forms, then our results include and improve some known results. [ABSTRACT FROM AUTHOR]

A series of poly(p-phenylene-1,3,4-oxadiazoles) (PODs) were synthesised from terephthalic acid (TPA) and hydrazine sulphate in fuming sulphuric acid via a recently developed procedure, namely, one step with three stages. The influence of the reaction temperature and time, and molar ratio of SO3/TPA on the cyclisation degree of POD was investigated. The structure of PODs was characterised by a Fourier transform infrared spectrophotometer, and the cyclisation degree was calculated based on the results of elemental analysis. The stability and fluidity of POD solutions with different cyclisation degrees were determined by viscometry. The filaments of PODs were formed through wet spinning, in which the POD solutions were directly extruded into a coagulating bath containing 40% sulphuric acid solution. The thermal resistance and structure of POD fibres were studied by thermogravimetric analysis, SEM and wide angle X-ray diffraction. The relationship between the fibre's properties and the cyclisation degree was discussed. Results show that the POD solutions with high cyclisation degree are stable and spinnable. The thermal, mechanical and chemical properties of fibres depend greatly on the cyclisation degree of POD fibre and post-treatment conditions. The higher the cyclisation degree of POD fibre, the better the properties, except for those fibres which have undergone extensive heat-treatment. The resulting POD fibres have good thermal stability and moisture regain, as well as proper mechanical properties. These fibers can be used as heat resistant filtering fabrics, and protective working clothes for firemen, metallurgists and welders. [ABSTRACT FROM AUTHOR]

In this paper, a sufficient condition is established for the controllability of neutral functional integro-differential inclusions with an unbounded delay in Banach spaces. The approach used is a fixed-point theorem for condensing maps due to Martelli and the theory of analytic semigroup of linear operators. [ABSTRACT FROM AUTHOR]

In this paper, the controllability of second-order differential and integrodifferential inclusions in Banach spaces are investigated. Two new results are obtained by using the theory of strongly continuous cosine families and a fixed-point theorem for multivalued maps. [ABSTRACT FROM AUTHOR]

Non-negative definite Lyapunov functions are employed to obtain sufficient conditions that guarantee boundedness of solutions of nonlinear functional discrete systems. The theory is illustrated with several examples. [ABSTRACT FROM AUTHOR]

Length-weight relationships ( LWRs) were determined for eleven endemic fish species [ Coreius guichenoti (Sauvage & Dabry de Thiersant, 1874), Glyptothorax sinensis (Regan, 1908), Leptobotia elongata (Bleeker, 1870), Leptobotia taeniops (Sauvage, 1878), Pseudobagrus crassilabris (Günther, 1864), Rhinogobio ventralis (Sauvage & Dabry de Thiersant, 1874), Saurogobio dabryi (Bleeker, 1871), Schizothorax chongi (Fang, 1936), Schizothorax kozlovi (Nikolskii, 1903), Schizothorax prenanti (Tchang, 1930) and Schizothorax wangchiachii (Fang, 1936)] from the middle reaches of the Jinsha River in southwest China. Samples were obtained between May 2004 and July 2013 using various types of fishing gear and electroshock fishing techniques. For each species, the sample size, length range, weight range, LWR, 95% confidence intervals of a and b, and coefficient of correlation were determined. Prior to this study, the LWRs for four species ( P. crassilabris, S. chongi, S. kozlovi and S. prenanti) were unknown. [ABSTRACT FROM AUTHOR]

Wuchang bream ( Megalobrama amblycephala) is an economically important fish in China. From a (GT)13-enriched genomic library, 20 microsatellites were developed. Nine of these 20 loci were polymorphic in a test population with allele numbers ranging from two to four, and the observed and expected heterozygosities ranging from 0.2609 to 0.7826 and from 0.3739 to 0.7546, respectively. In the cross-species amplifications, six of these nine loci were also polymorphic in white amur bream ( Parabramis pekinensis). These polymorphic microsatellite loci are potentially useful for population genetics of Wuchang bream and its closely related species. [ABSTRACT FROM AUTHOR]

The rice field eel ( Monopterus albus) is a fish of economic importance in China and some Asian countries. From a (GT) n-enriched genomic library, 30 microsatellites were developed by employing the fast isolation by AFLP of sequences containing repeats (FIASCO) protocol. Thirteen loci exhibited polymorphism with two to 13 alleles (mean 7.9 alleles/locus) in a test population and observed heterozygosity ranged from 0.3125 to 0.9688 (mean 0.7140). These loci should provide sufficient level of genetic variation to study the fine-scale population structure and reproductive ecology of the species. [ABSTRACT FROM AUTHOR]

Highly oxygen-rich SiOx thin films were prepared using a helicon plasma activated reactive evaporation technique. A small second-order optical nonlinearity was observed in the as-grown films, and thermal poling induced nonlinearity in the films was found to be much larger than that in stoichiometric SiO2 films. These phenomena were associated with the non-impurity defects in the oxygen-rich films. [ABSTRACT FROM AUTHOR]

Correction for 'A portable multi-collector system based on an artificial optical compound eye for stand-off laser-induced breakdown spectroscopy' by W. T. Li et al., J. Anal. At. Spectrom., 2017, 32, 1975–1979, DOI: 10.1039/C7JA00173H. [ABSTRACT FROM AUTHOR]

Correction for 'In situ classification of rocks using stand-off laser-induced breakdown spectroscopy with a compact spectrometer' by W. T. Li et al., J. Anal. At. Spectrom., 2018, 33, 461–467, DOI: 10.1039/C8JA00001H. [ABSTRACT FROM AUTHOR]

1. Poultry meat quality is affected by many factors, among which intramuscular fat (IMF) is predominant. IMF content affects tenderness, juiciness and flavour of meat. Krüppel-like transcriptional factors (KLFs) are important regulators of adipocyte differentiation. However, little is known about the KLF9 gene associated with poultry IMF deposition, especially intramuscular adipocyte differentiation. 2. Previous work has shown that chicken KLF9 was differentially expressed during adipogenesis of intramuscular preadipocytes differentiation. In this study, the function of KLF9 in chicken intramuscular preadipocytes differentiation was investigated. 3. In the chicken preadipocyte differentiation model, KLF9 expression showed a major increase with adipogenic induction. Overexpression of KLF9 down-regulated the expression of the adipogenic marker gene AP2, and impaired triglyceride accumulation. Knockdown of KLF9 in chicken intramuscular preadipocytes increased the expression of PPARG, CEBPA and AP2. In addition, it was proposed that KLF9 may regulate adipogenesis via lncRNAs NONGGAT002209.2, NONGGAT003346.2, NONGGAT000436.2 and NONGGAT006302.2 in chicken. 4. The data supported a novel role of KLF9 in regulating chicken intramuscular preadipocyte differentiation. Such findings may contribute to a more thorough understanding of chicken IMF deposition and the improvement of poultry meat quality. [ABSTRACT FROM AUTHOR]

Multimode tumour ablation therapy is a treatment method that combines cryoablation with radiofrequency ablation, guided by medical imaging technology and based on precise planning, targeting, monitoring, and control of the thermal energy delivered, with the aim of achieving a whole-body antitumour immune response to malignant tumours. To develop standardized criteria for the application of multimode tumour ablation therapy to malignant hepatic tumours, to facilitate actualization of the criteria in various hospitals, and to ensure therapeutic efficacy and safety, the Society of Interventional Therapy of the Chinese Anti-Cancer Association and the Solid Tumor Theranostics Committee of the Shanghai Anti-Cancer Association assembled experts who specialize in oncology to discuss this treatment method and to arrive at a clinical practice consensus guideline for the indications, contraindications, and techniques of multimode tumour ablation therapy for malignant hepatic tumours. [ABSTRACT FROM AUTHOR]

Objective: Despite aggressive therapeutic regimens, diffuse alveolar haemorrhage (DAH) is still associated with a high mortality rate in systemic lupus erythematosus (SLE). This study was carried out in patients with SLE-associated DAH with a focus on their therapeutic modality.Method: A retrospective review was performed in 839 Han Chinese lupus patients hospitalized for their DAH manifestation from May 2006 to December 2016.Results: There were 24 episodes in 17 cases (2.0% incidence), 15 females and two males aged 19-67 years (mean ± sd 38.2 ± 15.1 years). High disease activity [Systemic Lupus Erythematosus Disease Activity Index 2000 (SLEDAI-2K) 12-31, 19.8 ± 5.6] was found at the onset of DAH. All patients were treated with high-dose corticosteroid, followed by pulse methylprednisolone (70.6%), plasmapheresis (41.2%), pulse cyclophosphamide (35.3%), and rituximab (23.5%). Six patients (35.3%), including three with extracorporeal membrane oxygenation, died owing to acute respiratory failure. All patients receiving rituximab treatment survived with a follow-up period of 12-58 months (40.8 ± 21.1 months), and no further relapse was noted in three cases with a history of recurrent DAH episodes. In addition, there was a significant decrease in their lupus activity (SLEDAI-2K 21.5 ± 6.0 to 6.3 ± 1.7, p = 0.0286).Conclusion: In this single-centre series with SLE-associated DAH in Han Chinese patients, a beneficial effect of rituximab therapy was observed. [ABSTRACT FROM AUTHOR]

The aim of this study was to determine to what extent juvenile Japanese flounder can adapt to different stocking densities in captivity and to examine whether growth and some physiological parameters critical for welfare might be affected by different dissolved oxygen levels. Japanese flounder ( Paralichthys olivaceus) juveniles (initial weight 1.27 ± 0.04 g/fish) were reared at five stocking densities (500, 1,000, 1,500, 2,000, 2,500 ind/m3) and two levels of dissolved oxygen ( DO) concentration (5.5 ± 0.5 mg/L or 14 ± 2 mg/L) with duplicate tanks for each treatment in water-recirculating systems for 40 days. Survival and activity of superoxide dismutase ( SOD) were not affected either by stocking density or dissolved oxygen, whereas final body weight, specific growth rate ( SGR) and feed conversion efficiency ( FCE) of fish under low DO concentration decreased significantly with increasing stocking density. In contrast, growth of fish reared in high DO levels were unaffected by the stocking density. Furthermore, fish in this group had a higher feed intake and, consequently, grew faster ( SGR) and achieved a higher final weight than fish reared at the low DO level. A significant reduction in hemoglobin (Hb) concentration and red blood cell ( RBC) count of fish were recorded as DO concentration increased. Furthermore, the activity of protease decreased significantly with increasing stocking density and increased significantly with increasing DO concentration. The ventilation frequency results indicate that gill ventilation decreased significantly as DO levels increased. This study demonstrates that stocking density can affect the growth performance and physiological parameters critical for welfare of juvenile Japanese flounder. Also shown is that pure oxygen supplementation is an effective way to improve the growth of juvenile Japanese flounder when reared at a high stocking density. [ABSTRACT FROM AUTHOR]

This paper examined the sediment gain and loss in the river mouth reach of the Yangtze River by considering sediment load from the local tributaries, erosion/accretion of the river course, impacts of sand mining, and water extraction. A quantitative estimation of the contribution of the river mouth reach to the sediment load of the Yangtze River was conducted before and after impoundment of the Three Gorges Dam (TGD) in 2003. The results showed that a net sediment load loss of 1.78 million ton/yr (Mt/yr) occurred from 1965 to 2002 in the study area. The contribution of this reach to the sediment discharge into the sea is not as high as what was expected before the TGD. With impoundment of the TGD, channel deposition (29.90 Mt/yr) and a net sediment loss of 30.89 Mt/yr occurred in the river mouth reach from 2003 to 2012. The river mouth reach has acted as a sink but not a source of sediment since impoundment of the TGD, which has exacerbated the decrease in sediment load. Technologies should be advanced to measure changes in river channel morphology, as well as in water and sediment discharges at the river mouth reach. [ABSTRACT FROM AUTHOR]

Summary: Length‐weight and length‐length relationships were investigated for 13 freshwater fish species from the lower Jinsha River, southwest China (from 101°32′49.63″E; 26°35′38.27″N to 104°37′48.14″E; 28°45′59.55″N). Fish were sampled from five sites during 2014 and 2016, using trap‐nets, gillnets (major mesh size: 2–6 cm), longline and electrofishing. Length‐weight relationships for six and length‐length relationships for 12 species are the first report to FishBase, respectively. Moreover, new maximum length for 11 species are also presented to FishBase in this study. All regressions were highly significant (p < .001), with the coefficient of determination r2 > .950. These information will be helpful for management and conservation in local fishes and fisheries. [ABSTRACT FROM AUTHOR]

Summary: The length‐weight relationships and new total length are described for five fish species in the Pengxi River basin of the Three Gorges Reservoir. Fish were occasionally sampled from five sites between 2009 and 2014, using various gill nets (mesh size range 2–12 cm) and electrofishing. For four of the five species studied a new maximum total length not yet recorded in previous length‐weight estimates have been found. These data will help to convert length data from field studies in the Three Gorges Reservoir into weight and biomass. [ABSTRACT FROM AUTHOR]

This paper is concerned with entire solutions of a class of bistable delayed lattice differential equations with nonlocal interaction. Here an entire solution is meant by a solution defined for all (n,t) ∈ ℤ × ℝ. Assuming that the equation has an increasing traveling wave front with nonzero wave speed and using a comparison argument, we obtain a two-dimensional manifold of entire solutions. In particular, it is shown that the traveling wave fronts are on the boundary of the manifold. Furthermore, uniqueness and stability of such entire solutions are studied. [ABSTRACT FROM AUTHOR]

Two segments of plasmas with different densities, which are operated as the electron injector and accelerator, respectively, are designed to realize a cascaded laser wakefield accelerator. Particle-in-cell simulations indicate that the further acceleration of the electrons in the second uniform-density plasma relies on the injection and acceleration in the first stage. It is found that electrons trapped in the second wakefield period in the first stage can be seeded into the next stage with an optimized phase for efficient acceleration and reducing in the relative energy spread. And finally a 700 MeV electron beam with a relative rms energy spread about 0.6% and the normalized transverse emittance of 1.4π mm mrad was obtained after a 5.5-mm-long acceleration in a dark-current free cascaded laser wakefield accelerator. Our results demonstrate that, for a given laser energy, choices in laser and plasma parameters strongly affect the output electron beam energy and quality, and that all of these parameters can be controlled. [ABSTRACT FROM AUTHOR]