Theories Applied to Multimedia Network Foreign Language Teaching

The widespread application of network information and multimedia technology in teaching brings great changes to foreign language teaching environment and teaching objectives. The traditional teacher-centered teaching mode changes into the learner-centered one. Modern teaching theories provide powerful theoretical support for foreign language teaching in the context of multimedia network information. This paper probes into constructivism theory, communicative teaching theory, input and output hypotheses which are applied in multimedia network foreign language teaching and their practical use in teaching

The least-squares solutions of inconsistent matrix equation over symmetric and antipersymmetric matrices

AbstractIn this paper, we are concerned with the following two problems. In Problem I, we describe the set S of real n × n symmetric and antipersymmetric matrices such that minimize the Frobenius norm of LG − E for G, E in Rn × n. In Problem II, we find the unique Ľ in the setsfS, satisfying ∥L∗ − L∥ = minLϵS ∥L∗ − L∥, where L∗ ϵ Rn × n is a given matrix and ∥ · ∥ is the Frobenius norm. We derive a general expression of the set S. For Problem II, we prove the existence and the uniqueness of the solution and provide the expression of this unique solution. We also report some numerical results to support the theory established in the paper

Controllable terahertz radiation from a linear-dipole-array formed by a two-color laser filament in air

We have demonstrated the effective control on carrier-envelope phase, angular distribution as well as peak intensity of a nearly single-cycle terahertz pulse emitted from a laser filament formed by two-color, the fundamental and the corresponding second harmonics, femtosecond laser pulses propagating in air. Experimentally, such control has been performed by varying the filament length and the initial phase difference between the two-color laser components. A linear-dipole-array model, including the descriptions of the both generation (via laser field ionization) and propagation of the emitted terahertz pulse, is proposed to present a quantitative interpretation of the observations. Our results contribute to the understanding of terahertz generation in a femtosecond laser filament and suggest a practical way to control the electric field of terahertz pulse for potential applications

Frequency tuning for broadband terahertz emission from two-color laser-induced air plasma

Effective manipulation of broadband terahertz emission, especially on spectrum tuning, is of great importance for many applications. We demonstrate a method to realize frequency tuning of terahertz emissions from two-color laser-induced air plasmas. The terahertz central frequency is switched from 0.56 to 0.82 THz by changing the polarization state of the fundamental wave with a quarter-wave plate. Based on numerical simulation, it is found that this frequency tuning is due to the birefringence effect induced by the fundamental wave on the second harmonic inside the filament, which leads to a discrepancy on the polarization chirality of the two-color laser components. Two-color lasers with opposite chirality will emit terahertz radiation with higher central frequency compared to two-color lasers with the same chirality at moderate laser intensity

Frequency blue shift of terahertz radiation from femtosecond laser induced air plasmas

The peak frequency of the terahertz radiation generated from the femtosecond laser-induced air plasmas is blue shifted with the increased second harmonics intensity when a high voltage is added upon the air plasmas. This blue shift is the result of the DC-biased field from the high voltage plus the AC-biased field from the second harmonics, indicating that this terahertz radiation frequency peak is tunable by varying the two field components. This tunable frequency peak is significant to various applications such as remote sensing and material characterization

In Vivo Bioassay of Recombinant Human Growth Hormone Synthesized in B. mori Pupae

The human growth hormone (hGH) has been expressed in prokaryotic expression system with low bioactivity previously. Then the effective B. mori baculovirus system was employed to express hGH identical to mature hGH successfully in larvae, but the expression level was still limited. In this work, the hGH was expressed in B. mori pupae by baculovirus system. Quantification of recombinant hGH protein (BmrhGH) showed that the expression of BmrhGH reached the level of approximately 890 μg/mL pupae supernatant solution, which was five times more than the level using larvae. Furthermore, Animals were gavaged with BmrhGH at the dose of 4.5 mg/rat.day, and the body weight gain (BWG) of treated group had a significant difference (P < .01) compared with the control group. The other two parameters of liver weight and epiphyseal width were also found to be different between the two groups (P < .05). The results suggested that BmrhGH might be used as a protein drug by oral administration

Bessel terahertz pulses from superluminal laser plasma filaments

Terahertz radiation with a Bessel beam profile is demonstrated experimentally from a two-color laser filament in air, which is induced by tailored femtosecond laser pulses with an axicon. The temporal and spatial distributions of Bessel rings of the terahertz radiation are retrieved after being collected in the far field. A theoretical model is proposed, which suggests that such Bessel terahertz pulses are produced due to the combined effects of the inhomogeneous superluminal filament structure and the phase change of the two-color laser components inside the plasma channel. These two effects lead to wavefront crossover and constructive/destructive interference of terahertz radiation from different plasma sources along the laser filament, respectively. Compared with other methods, our technique can support the generation of Bessel pulses with broad spectral bandwidth. Such Bessel pulses can propagate to the far field without significant spatial spreading, which shall provide new opportunities for terahertz applications

Elevated circulating GPHB5 levels in women with insulin resistance and polycystic ovary syndrome: A cross-sectional study and multiple intervention studies

ObjectiveGPHB5 has been found to be associated with glucose and lipid metabolism in animal studies. However, the association of GPHB5 with IR and metabolic disorders remains unknown, and there is a lack of research in humans. Our aim in this study was to investigate the relationship between circulating GPHB5 and metabolic disorders in humans.MethodsBioinformatics analysis was performed to understand the relationship between GPHB5 and metabolic disorders. GPHB5 mRNA expression in mice and rats was determined using RT-qPCR. Circulating GPHB5 concentrations were measured with an ELISA kit. EHC and OGTT were performed in humans.ResultsBioinformatics analysis shows that GPHB5 is associated with metabolic disorders and PCOS. GPHB5 mRNA expression levels in the metabolic-related tissues of HFD-fed mice, db/db and ob/ob mice, and PCOS rats were significantly higher than those of WT mice or rats. In human studies, we find that circulating GPHB5 levels were significantly higher in women with IR and PCOS. GPHB5 levels were positively correlated with age, BMI, WHR, BP, FBG, 2 h-BG, FIns, 2 h-Ins, TC, LDL-C, HbA1c, and FFA, but negatively correlated with adiponectin. Furthermore, GPHB5 was positively correlated with DHEAS and FAI, while negatively correlated with SHBG, FSH, SHBG and FSH. The increased GPHB5 concentration was related to IR and PCOS. After the treatment of metformin, GLP-1RA (Lira), and TZDs, circulating GPHB5 levels were decreased.ConclusionsOur results reveal that circulating GPHB5 could be a biomarker and potential therapeutic target for IR and PCOS in women

Spectral interference of terahertz pulses from two laser filaments in air

Spectral interference is experimentally demonstrated by two terahertz pulses emitting from filaments induced by two successive femtosecond laser pulses in air. Here, a leading pulse is set to be weaker than a trailing pulse and their temporal separation is larger than the pulse duration of the terahertz pulses. When the leading pulse is stronger than the trailing pulse, the frequency modulation within the whole terahertz envelope is greatly deteriorated due to nonlinear effects applying on the trailing pulse through the plasmas generated by the leading pulses. Such unique terahertz spectrum may find applications in terahertz spectroscopy