Publications by authors named "Sheng-ping Chen"

In order to explore the mechanism of neonatal spontaneous breathing, the difference of oxygen and carbon dioxide between umbilical cord arteries and veins before the start of spontaneous breathing after birth has been analyzed among people. In this part, the related information is analyzed individually. After all fetal parents signed the informed consent before birth, and before the newborn was born and did not breathe, the umbilical cord was exposed as quickly as possible, and the heparinized arterial indwelling needle was inserted into the umbilical artery and umbilical vein in the direction of newborn and placenta, and then blood was taken continuously.

View Article and Find Full Text PDF

The fetus has no actual respiration, and the newborn begins to breathe after birth. We assume that the first breath dominantly generated by hypoxia. In this study, the changes and lowest limit of blood oxygen partial pressureof umbilical artery (PuaO) after chemoreceptor were analyzed to explore the mechanism of neonatal spontaneous breathing.

View Article and Find Full Text PDF

An all-fiber linearly polarized supercontinuum (SC) laser source with 93 W average output power and spectrum ranging from 520 nm to 2300 nm is experimentally demonstrated. The linearly-polarized SC is generated in a piece of 2.6 m long polarization-maintaining photonic crystal fiber (PM-PCF), pumped by a polarization-maintaining picosecond Yb-doped master oscillator power amplifier (PM-MOPA).

View Article and Find Full Text PDF

High power LP mode supercontinuum is generated from 25/250 large mode area (LMA) fiber. A mechanical long period grating (LPG) is utilized to control the transverse modes in the LMA fiber to realize the LP mode supercontinuum generation in a master oscillator power amplifier (MOPA) configuration. The generated LP mode supercontinuum covers the spectral range from ~900 nm to ~2100 nm with a -30-dB spectral width of ~1200 nm and 50% optical to optical conversion efficiency.

View Article and Find Full Text PDF

We experimentally demonstrate an all-fiber, ultraviolet-enhanced, supercontinuum generation in a specifically designed seven-core photonic crystal fiber pumped by a picosecond Yb-doped master oscillator power amplifier (MOPA). The MOPA source is seeded by a giant-chirped Yb-doped mode-locked fiber laser operating in the dissipative-soliton-resonance (DSR) region. The DSR is achieved by using a nonlinear optical loop mirror (NOLM) with a fundamental repetition rate of 4.

View Article and Find Full Text PDF

We present the results of numerical simulations of dissipative soliton generation using nonlinear Schrödinger equations in an all-normal-dispersion (ANDi) mode-locked fiber laser based on a nonlinear optical loop mirror (NOLM). Firstly, systematic and computationally intensive analysis of the pulse state distributions in two-dimensional parameter spaces of an ANDi fiber laser was conducted. In addition, we determined that unstable non-vanishing regions including pulsation and noise-like pulses are directly related to the saturable absorptions of NOLMs and that two critical filter bandwidths separate those regions from stable ones.

View Article and Find Full Text PDF

We propose a novel approach for achieving selective transverse mode operation of few-mode all-fiber lasers. Lasing in a specific transverse mode is enabled by employing a pair of few-mode fiber Bragg gratings as an efficient transverse mode selector. As a proof-of-principle, we have implemented a ytterbium-doped all-fiber laser operating in the second-order (LP) transverse mode.

View Article and Find Full Text PDF

We report a hybrid passively mode-locked dumbbell-shaped fiber laser based on a nonlinear optical loop mirror and a nonlinear amplifying optical fiber-loop mirror. The laser produced noise-like pulses with repetition rate of 8.85 MHz and pulse energy of 16.

View Article and Find Full Text PDF

A novel all-fiberized dumbbell-shaped mode-locked fiber laser was developed to directly generate 80 nJ dissipative solitons, which can be linearly compressed from 85 to 1.2 ps externally with a diffraction grating pair. The pulse peak power reached 42 kW after compression.

View Article and Find Full Text PDF

This paper presents an all fiber high power picosecond laser at 1016 nm in master oscillator power amplifier (MOPA) configuration. A direct amplification of this seed source encounters obvious gain competition with amplified spontaneous emission (ASE) at ~1030 nm, leading to a seriously reduced amplification efficiency. To suppress the ASE and improve the amplification efficiency, we experimentally investigate the influence of the gain fiber length and the residual ASE on the perforemance of the 1016 nm amplifier.

View Article and Find Full Text PDF

Pulsed fibre lasers operating in the eye-safe 2 μm spectral region have numerous potential applications in areas such as remote sensing, medicine, mid-infrared frequency conversion, and free-space communication. Here, for the first time, we demonstrate versatile 2 μm ps-ns pulses generation from Tm-based fibre lasers based on frequency shifted feedback and provide a comprehensive report of their special behaviors. The lasers are featured with elegant construction and the unparalleled capacity of generating versatile pulses.

View Article and Find Full Text PDF

We demonstrate Watt-level flat visible supercontinuum (SC) generation in photonic crystal fibers, which is directly pumped by broadband noise-like pulses from an Yb-doped all-fiber oscillator. The novel SC generator is featured with elegant all-fiber-integrated architecture, high spectral flatness and high efficiency. Wide optical spectrum spanning from 500 nm to 2300 nm with 1.

View Article and Find Full Text PDF

A largely simplified and highly efficient all-fiber-based synchronously pumping scheme is proposed. The synchronization between pump light and the cavity round-trip can be achieved by adjusting the repetition rate of pumping light without the requirement of altering the cavity length. Based on this scheme, we achieved generating narrow linewidth highly efficient 1120 nm pulse directly from an all-fiber Raman cavity.

View Article and Find Full Text PDF

We report flexible dissipative soliton generation from an all-fiberized all-normal-dispersion (ANDi) long cavity actively mode locked ytterbium doped fiber laser based on improved harmonic mode locking technique. The laser is featured with unusually wide and fine tunabilities in repetition rate and operating wavelength, meanwhile superior stability is maintained. The repetition rate of the laser can be flexibly controlled from 226 kHz to 6.

View Article and Find Full Text PDF

We demonstrate nanosecond scale rectangular wave-breaking-free pulse generation in an actively mode locked Yb-doped fiber laser based on a combined action of active periodic cavity loss modulation and nonlinear polarization rotation effect. The pulse width of the laser can be controlled in the range of 890 ps to above 124 ns instantaneously by adjusting the electrical signal applied on the modulator. As high as 19.

View Article and Find Full Text PDF

To reveal novel insights into the inhibition of BCR-ABL tyrosine kinase, pharmacophore mapping studies were performed for a series of phenylaminopyrimidine-based (PAP) derivatives, including imatinib (Gleevec). A seven-point pharmacophore model with one hydrophobic group (H), two hydrogen bond donors (D) and four aromatic rings (R) was developed using phase (pharmacophore alignment & scoring engine). The pharmacophore hypothesis yielded a statistically significant 3D-QSAR model, with a correlation coefficient of 0.

View Article and Find Full Text PDF

Deoxybostrycin (1) is an anthraquinone compound derived from the marine mangrove fungus Nigrospora sp. No. 1403 and has potential to be a lead for new drugs because of its various biological properties.

View Article and Find Full Text PDF

Background: The inhibition of the activity of β-secretase (BACE-1) is a potentially important approach for the treatment of Alzheimer disease. To explore the mechanism of inhibition, we describe the use of 46 X-ray crystallographic BACE-1/inhibitor complexes to derive quantitative structure-activity relationship (QSAR) models. The inhibitors were aligned by superimposing 46 X-ray crystallographic BACE-1/inhibitor complexes, and gCOMBINE software was used to perform COMparative BINding Energy (COMBINE) analysis on these 46 minimized BACE-1/inhibitor complexes.

View Article and Find Full Text PDF

Background: In order to identify novel chemical classes of β-secretase (BACE-1) inhibitors, an alternative scoring protocol, Principal Component Analysis (PCA), was proposed to summarize most of the information from the original scoring functions and re-rank the results from the virtual screening against BACE-1.

Method: Given a training set (50 BACE-1 inhibitors and 9950 inactive diverse compounds), three rank-based virtual screening methods, individual scoring, conventional consensus scoring and PCA, were judged by the hit number in the top 1% of the ranked list. The docking poses were generated by Surflex, five scoring functions (Surflex_Score, D_Score, G_Score, ChemScore, and PMF_Score) were used for pose extraction.

View Article and Find Full Text PDF

Since the 1960s, more than 20,000 compounds were discovered from marine organisms. In this paper we performed a quantitative analysis for the novel marine natural products reported between 1985 and 2008. The data was extracted mainly from the reviews of Faulkner and Blunt [1-26].

View Article and Find Full Text PDF

A high power picosecond laser is constructed in an all fiber master oscillator power amplifier (MOPA) configuration. The seed source is an ytterbium-doped single mode fiber laser passively mode-locked by a semiconductor saturable absorber mirror (SESAM). It produces 20 mW average power with 13 ps pulse width and 59.

View Article and Find Full Text PDF

Objective: To observe the clinical efficacy of Yinzhihuang Oral Liquid (YOL) to prevent the premature infantile jaundice.

Methods: After excluded hemolytic, suffocation, infection, and the very low birth weight, 242 cases of premature infants were randomly assigned to two groups, the treatment group and the control group. Both groups were taken conventional procedures, such as warmth, feeding, and blood glucose monitoring, and the treated group was administered YOL 5 mL each time, twice daily additionally, and the control group without any treatment.

View Article and Find Full Text PDF

Successful embryo implantation depends on the ability of the trophoblast cells to invade the endometrium and the receptivity of the endometrium. Unlike tumor invasion, trophoblast invasion is spatio-temporaly restricted. Transforming growth factor (TGF)-beta is a key inhibitory factor in the invasion of early trophoblast cells.

View Article and Find Full Text PDF

Two new natural products, tenelate A (1) and B (2), together with the known compound, tenellic acid C (3), were isolated from the mangrove endophytic fungus Talaromyces sp. (SBE-14), from the South China Sea. Their structures were elucidated by spectroscopic methods, mainly 1D and 2D NMR techniques.

View Article and Find Full Text PDF

The effect of polarization controlling on coherent beam combining of two-fiber laser arrays of interferometric configuration is researched. Three kinds of arrays, built on the basis of Michelson and Mach-Zehnder interferometers, are investigated experimentally. It is found that polarization controlling is not necessary for coherent beam combining of the Michelson interferometric array but necessary for that of Mach-Zehnder interferometric arrays.

View Article and Find Full Text PDF