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Background and Objectives: EUS has become a very frequently used procedure for both diagnostic and therapeutic indications. However, skilled operators are essential for improved outcomes and patient safety which make efficient training and certification programs essential. Our aim was to explore the acquisition and assessment of EUS competencies in China as practiced in the past, today, and in the future. Methods: We identified key opinion leaders (KOLs) from hospitals in different cities in China. Each KOL answered 43 questions regarding demographics and EUS experience, their learning experience as a trainee, experience as a supervisor, and their thoughts about current and future training. Descriptive statistics were used for reporting the results. Results: Eleven men and five females from eight major Chinese cities (Beijing, Changsha, Chengdu, Chongqing, Guangzhou, Shanghai, Shenzhen, and Wuhan) were included. They offered a good variance regarding age (33-53 years old), EUS experience (½-20 years), and performed procedures (20-6000 procedures). Most (n = 13) learned EUS through apprenticeship training model but three were self-taught. The KOLs also used the apprenticeship model to train their own trainees. First, they demonstrated EUS for median 2 months before their trainees took over the scope and performed a median 50 supervised procedures during a median of 3 months. Then they were allowed to perform EUS procedures independently. Simulation-based training and standardized assessment of competence were used very sparingly, but most of the KOLs wanted to shift towards these contemporary methods in the future. Conclusions: The classical apprenticeship training is still used to learn EUS in China and the amount of training required before being allowed to practice independently varies considerably. Several of the KOLs requested improved conditions for training and wanted a standardized curriculum leading to certification of new EUS operators based on a valid assessment of competence.

Additional file 1: Table S1. A Summary of 1044 Radiomics Features, Table S2. A summary of radiomics features significantly associated with treatment response of neoadjuvant chemotherapy.

Interfaces between the perovskite active layer and the charge-transport layers (CTLs) play a critical role in both efficiency and stability of halide-perovskite photovoltaics. One of the major concerns is that surface defects of perovskite could cause detrimental nonradiative recombination and material degradation. In this work, we addressed this challenging problem by inserting ultrathin alkali-fluoride (AF) films between the tri-cation lead-iodide perovskite layer and both CTLs. This bilateral inorganic walls strategy makes use of both physical-blocking and chemical-anchoring functionalities of the continuous, uniform and compact AF framework: on the one hand, the uniformly distributed alkali-iodine coordination at the perovskite-AF interfaces effectively suppresses the formation of iodine-vacancy defects at the surfaces and grain boundaries of the whole perovskite film, thus reducing the trap-assisted recombination at the perovskite-CTL interfaces and therewith the open-voltage loss; on the other hand, the impermeable AF buffer layers effectively prevent the bidirectional ion migration at the perovskite-CTLs interfaces even under harsh working conditions. As a result, a power-conversion efficiency (PCE) of 22.02% (certified efficiency 20.4%) with low open-voltage deficit (< 0.4V) was achieved for the low-temperature processed inverted planar perovskite solar cells. Exceptional operational stability (500 h, ISOS-L-2) and thermal stability (1000 h, ISOS-D-2) were obtained. Meanwhile, a 35.7% PCE was obtained under dim-light source (1000 lux white LED light) with the optimized device, which is among the best records in perovskite indoor photovoltaics.

A new loop-mediated isothermal amplification (LAMP) method for the detection of Cyprinid herpesvirus 2 (CyHV-2) was developed. Following the synthesis in vitro of a 413 bp DNA fragment of CyHV2 DNA-dependent DNA polymerase gene by overlap extension PCR using 11 overlapping oligo primers designed according to the gensome sequences information of CyHV2 published in GenBank, a set of 6 LAMP primers were designed based on the synthesized DNA fragment, and the LAMP assay was primarily established after preparation of target gene fragments, optimization of reaction conditions, products identification, sensitivity and specificity tests. Results showed the developed LAMP assay was a rapid, specific and sensitive method for CyHV2 detection, with a ladder-like pattern of amplification bands from about 177 bp incubation at 64°C for 30 min by using agarose gel electrophoresis. The detection limit could reach about 15 copies of cloned viral genomic fragments, and no cross reaction with Aeromonas veronii, Aeromonas hydrophila, Pseudomonas fluorescens and Streptococcus common pathogens isolated from fish detection by this approach.

With the unveiling of molecular and atomic dynamics, scientists crave finer and faster tools to communicate with the microworld. Attosecond pump-probe enjoys its reputation as the fastest camera, hinting ultrafast movements in the delay graph. To employ this camera, the stability and delay control should have very great accuracy comparable to the camera resolution. It is also of significant importance for stabilizing the carrier envelope phase (CEP) in few-cycle laser field. When dealing with a huge quantity of data, conventional Fourier transform algorism is challenging in high-speed control. Here we put forward the efficient calculation method, fast Fourier transform (FFT) algorism in Mach-Zehnder interferometer for arm length locking and f-2f for CEP locking. In the interferometer locking, 532 nm continuous wave laser is used in the Mach-Zehnder interferometer, and the phase of the FFT term corresponding to the delay between the two arms of the interferometer serves as a feedback signal on piezo transducer (PZT) in the delay line to reduce the change of the arm length. In the CEP control experiment, data to be analyzed are the f-2f spectrum interference fringes recorded by the spectrometer. The CEP values are obtained from the first order of FFT module output of the integrated spectrum interference fringes, and a labview program examines the relative phase drift and sends a feedback voltage signal to the PZT through the proportion integration differentiation module to compensate slow CEP drift after the chirped pulse amplification system by changing the insert length of a prism pair. The results show that the root mean square (RMS) of the arm length difference is 1.24 nm (4.1 attosecond for light to travel) per meter in the interferometer locking over 12 h, and the RMS of CEP is 227 mrad under 3 ms integration time in the CEP locking over 20 min. These results are able to meet the requirement of the accuracy for attosecond pulse generation and attosecond pump-probe experiments. We also use FFT to stabilize the CEP and relative time simultaneously in the waveform synthesis for 8 h (Huang P, Fang S, Gao Y, Zhao K, Hou X, Wei Z 2019 Appl. Phys. Lett. 115 031102), the phase-locking system results in a CEP stability of 280 mrad and a relative time stability of 110 as at a repetition rate of 1 kHz. These results imply that the FFT is versatile and reliable in ultrafast control.

The accurate and precise controlling of the attosecond time delay between the sub-pulses within a hundredth of an optical cycle is the key ingredient for the sophisticated custom-tailored coherent waveform synthesizer. The attosecond delay control technique commonly experiences the “complete” characterization of the ultrashort sub-cycle pulses, which includes the spatiotemporal pulse characterization of the synthesized waveform and the attosecond relative delay between the parent pulses. In this work, the relative time delay between spectrally separated ultrashort parent pulses is characterized in an interferometer scheme with a background-free transient-grating frequency-resolved optical grating (TG-FROG). The TG-FROG geometry accurately measures the full time-dependent intensity and phase of ultrashort laser pulses in a wide range of regime (from ultraviolet to infrared) and offers significant advantages over other nonlinear-optical processes geometries (i.e., the polarization-gate-FROG, the self-diffraction-FROG, the second-harmonic generation-FROG and the third-harmonic-generation-FROG). The attosecond measurement accuracy is achieved for the first time, to the best of our knowledge. In this experiment, the output of a carrier-envelope-phase-stable Ti:sapphire amplifier (sub-30-fs, over-1-mJ, 1 kHz) is spectrally broadened in a neon-filled hollow-core fiber with an inner diameter of 250μm. The transmission through the pressure-gradient hollow-core fiber results in an mJ-level octave-spanning whitelight supercontinuum, supporting a sub-3-fs Fourier transform-limited pulse. The supercontinuum is spectrally divided into two parent pulses by using a dichroic mirror. The sub-pulses are individually compressed by the custom-designed double-chirped mirrors and wedge pairs. The short and long wavelength pulses are separately compressed in few-cycle regime, yielding pulses with 6.7 fs and 9.8 fs, respectively. This technique overcomes the bottlenecks in the traditional delay measurement and should be applicable for many ultra-broadband pulse characterizations with extremely simple and alignment-free delay control device used. Furthermore, this new method will be easily adapted for the ultra-broadband two-dimensional electronic spectroscopy, the advanced temporal cloaking, and the field of sub-cycle arbitrary coherent waveform synthesizer for controlling strong-field interactions in atoms, molecules, solids, and nanostructures. We foresee that in the near future this novel technology will be very attractive for various applications in the next-generation light sources such as the Synergetic Extreme Condition User Facility in Beijing, China.

Coherent synthesis of laser pulses is a major trend in the generation of ultrafast pulse field. There is no good way to compensate for the whole spectrum when the spectrum of ultrashort pulses is wide enough to reach an octave, so it is difficult to realize a sub-cycle pulse in a single-path laser system even if the spectrum range is wide enough. In this paper, 0.8 mJ, 30 fs laser pulses at 1 kHz repetition rate with 790 nm center wavelength from a Ti:sapphire chirped pulse amplifier (CPA) system are focused into hollow fiber with an inner diameter of 250 μm and a length of 1 m to produce an octave-spanning white-light supercontinuum (450-950 nm). Using this supercontinuum, we conduct two sets of comparative experiments. 1) We split the supercontinuum into two pulses with different spectrum ranges (450-750 nm and 650-1000 nm) by a dichroic mirror (HR, 500-700 nm; HT, 700-1000 nm), and we compress the two pulses by the double-chirped mirrors and wedge pairs to generate two few-cycle pulses:the long and short wavelength yielding pulses are 7.9 fs and 6.1 fs, respectively. Then we coherently synthesize two pulses by using another dichroic mirror, and controlling the relative time delay between the two pulses, and thus we synthesize a pulse of 4.1 fs. 2) We directly compress the supercontinuum by the double-chirped mirrors and wedge pairs, and obtain an optimization result of 5.3 fs, of which the pulse duration is wider than that in experiment 1. In these comparative experiments, the advantage of coherent synthesis for shorter pulse duration is preliminarily verified. Besides, the balanced optical cross-correlator technique is used to lock the relative time delay between two pulses. The root-mean-square value of relative time delay drift is less than 80 as in the case with feedback control loop, which ensures the stability of coherent synthesis system. This scheme can be adopted to accurately compensate for the dispersion and obtain the sub-cycle synthesized pulse, which is useful for generating the high harmonic and atto-second pulse.

This paper investigates the absorptive reduction and the width narrowing of electromagnetically induced transparency (EIT) in a thin vapour film of λ-type atoms confined between two dielectric walls whose thickness is comparable with the wavelength of the probe field. The absorptive lines of the weak probe field exhibit strong reductions and very narrow EIT dips, which mainly results from the velocity slow-down effects and transient behaviour of atoms in a confined system. It is also shown that the lines are modified by the strength of the coupling field and the ratio of L/λ, with L the film thickness and λ the wavelength of the probe field. A simple robust recipe for EIT in a thin medium is achievable in experiment.

ZnO, as a wide-band gap semiconductor, has recently become a new research focus in the field of ultraviolet optoelectronic semiconductors. Laser molecular beam epitaxy (L-MBE) is quite useful for the unit cell layer-by-layer epitaxial growth of zinc oxide thin films from the sintered ceramic target. The ZnO ceramic target with high purity was ablated by KrF laser pulses in an ultra high vacuum to deposit ZnO thin film during the process of L-MBE. It is found that the deposition rate of ZnO thin film by L-MBE is much lower than that by conventional pulsed laser deposition (PLD). Based on the experimental phenomena in the ZnO thin film growth process and the thermal-controlling mechanism of the nanosecond (ns) pulsed laser ablation of ZnO ceramic target, the suggested effective ablating time during the pulse duration can explain the very low deposition rate of the ZnO film by L-MBE. The unique dynamic mechanism for growing ZnO thin film is analyzed. Both the high energy of the deposition species and the low growth rate of the film are really beneficial for the L-MBE growth of the ZnO thin film with high crystallinity at low temperature.

ZnO complex 3D nano-structures have been self-organized on Al2O3 (0 0 0 1) substrate by laser molecular beam epitaxy (L-MBE). It is shown by AFM morphology that the structure is composed of ID quantum dot chains (QDCs) and larger nano-islands at the nodes of QDCs. The formation mechanism of the nano-structure is also investigated. XRD results indicate that the nano-structure is highly c-axis oriented, with the aligned in-plane oriented domains. Time-integrated photoluminescence (TIPL) of the sample shows obvious blue-shift and broadening of the near band-edge (NBE) emission at room temperature, which are related to the quantum confinement effects. Time-resolved PL (TRPL) result shows bi-exponential decay behavior of ZnO QDCs, with a fast decay time of 38.21 ps and a low decay time of 138.19ps, respectively, which is considered to be originated from the interdot coupling made by coherent emission and reabsorption of the photons in QDCs. (C) 2007 Elsevier B.V. All rights reserved.

The Eu, Tb co-doped SiO2 matrix tricolor fluorescence system was prepared by sol-gel technique. Red emission at 618 nm, green emission at 543 nm and blue emission at 350–500 nm were observed in the PL spectra of the sample, indicating that Eu3+, Eu2+ and Tb3+ ions coexisted in the matrix. In the co-doped sample, the blue emission of Eu2+ was much stronger than that of the sample single doped with Eu, which implied that the electron transfer between Eu3+ and Tb3+ maybe happened in the SiO2 matrix. The influences of the annealing temperature and Tb concentration on the PL spectra of the samples were investigated. The optimal doped concentration of Tb was determined to be 0.2% and the optimal annealing temperature 850°C. Annealed at 600°C, Tb3+ had a sensitizing effect on Eu3+ in the SiO2 matrix, and the emission intensity of Eu3+ in the Eu, Tb co-doped sample was more than four times that of the single doped sample, which could be attributed to the energy transfer from Tb3+ to Eu3+.

In this paper the multiwalled carbon nanotubes (MWNTs) were synthesized by a chemical vapour deposition and the SEM graph shows that the sample has good construction. The micro-Raman spectrum shows the characteristic line of the MWNTs and an additional line produced by the defects on the outer surface of MWNTs. The photoluminescence (PL) spectra observed experimentally are variable under different excitation wavelengths and the strong excitation wavelength dependence of luminescence indicates a distribution of emitters which include electron pi in excited states and the Van Hove singularities. The absorption spectra confirm the transition channels which are consistent with the PL emission.

We report the frequency dependence of polarization mode dispersion (PMD) in a PMD compensator based on six cascaded birefringent crystals separated by Faraday rotators. When all crystal axes are aligned, the device can compensate for the first-order PMD. However, if all crystal axes are coupled with arbitrary angles, it can compensate for high-order PMD. The variations of differential group delay and principal state of polarization with optical frequency are analysed. The PMD vector and Stokes components of the device versus wavelength are measured. The theoretical simulations agree well with the experimental results.

A high yielding rice variety mutant (Oryza sativa L., Zhenhui 249) with low chlorophyll b (Chl b) has been discovered in natural fields. It has a quality character controlled by a pair of recessive genes (nuclear gene). The partial loss of Chl b in content affects the efficiency of light harvest in a light harvest complex (LHC), thus producing the difference of the exciting energy transfer and the efficiency of photochemistry conversion between the mutant and wild-type rice in photosynthetic unit. The efficiency of utilizing light energy is higher in the mutant than that in the wild-type rice relatively. For further discussion of the above-mentioned difference and learning about the mechanism of the increase in the photochemical efficiency of the mutant, the pico-second resolution fluorescence spectrum measurement with delay-frame-scanning single photon counting technique is adopted. Thylakoid membranes of the mutant and the wild-type rice are excited by an Ar+ laser with a pulse width of 120 ps, repetition rate of 4 MHz and wavelength of 514 nm. Compared with the time and spectrum property of exciting fluorescence, conclusions of those ultrafast dynamic experiments are: 1) The speeds of the exciting energy transferred in photo-system I are faster than that in photo-system II in both samples. 2) The speeds of the exciting energy transfer of mutant sample are faster than those of the wild-type. This might be one of the major reasons why the efficiency of photosynthesis is higher in mutant than that in the wild-type rice.

Concave diffraction gratings (CDGs) have the advantages of being compact, time reliability, cost effective, and channel spacing accuracy. These devices can be used in the wavelength division multiplexing (WDM) systems and micro-spectrometer devices. However, comparing with arrayed waveguides gratings (AWGs), the development of traditional CDGs is far from satisfactory. Because the traditional CDGs need deeply etched facets and perfect grating profiles to reduce the insertion losses, which will increase the difficulty in etching process. In order to solve this problem, Bragg reflectors based CDGs (Bragg-CDGs) are proposed. This structure can greatly reduce the insertion loss, and reduce the difficulty in etching process. The performance of the Bragg-CDG is determined by both the reflection condition of the Bragg reflectors and the diffraction condition of the CDG. With the Bragg reflection condition determined, the diffraction condition of Bragg-CDG will have a major influence on the performance of device. For successive strips based Bragg-CDG, the number of Bragg periods per diffraction grating period is an important parameter of Bragg-CDG. The diffraction condition of concave gratings is closely related to this parameter. This parameter has an effect on the performance of Bragg-CDG, specially termed resolution, the free spectrum range, and the diffraction efficiency. The effect of the number of Bragg periods per diffraction grating period on the Bragg diffraction grating is studied by theoretical analysis. In addition, four Bragg-CDGs with different numbers of Bragg periods are studied using the finite-difference time domain method. The results show that with sizes of diffraction gratings fixed, the resolution of Bragg-CDG does not have a significant improvement by changing the number of Bragg periods per diffraction grating period; the total number of diffraction orders is proportional to the number of Bragg periods per diffraction grating period. The Bragg-CDG with a single Bragg period per grating period has a maximum diffraction efficiency, since it has the minimal number of diffraction orders; in addition, with the increase of the number of Bragg periods per diffraction grating period, the free spectrum range of the main diffraction order gradually decreases. This research can contribute to the development of the demultiplexer with the low insertion loss, the high resolution, and the wide operating waveband.

A theory on spatial solitons in photovoltaic (PV)-photorefractive (PR) crystals for short circuits is developed that gives rise to spatial solitons due to both a bulk PV effect and spatial nonuniform screening of the external field. When the PV effect is neglected these solitons are screening solitons. When the external field is absent these solitons are PV solitons in short and open circuits and it is predicted that grey solitons exist in PV-PR crystals for short circuits. We also show theoretically that PV nonlinearity can be switched from self-defocusing to self-focusing (or vice versa) by adding the external field.

The Raman-enhanced polarization beats (REPB) with phase-conjugation geometry in carbon disulfide are investigated using chaotic and phase-diffusion models. The overall accuracy of using REPB to measure the resonant frequency of Raman-active vibrational mode is determined by the relaxation rates of the Raman mode and the molecular-reorientational grating. Different stochastic models of the laser field only affect the sixth- and fourth-order coherence function. The difference between the REPB and the fourth-order coherence on ultrafast modulation spectroscopy is discussed as well from a physical viewpoint.

The controllable growth processes of ZnO nanowires by evaporation of metal zinc with high purity and its luminescence properties have been investigated in detail. Firstly, the power of ZnO nanowires with high yield and homogeneous dimension was synthesized using the special quartz boat at 600°C. Then, the oriented ZnO nanowires with about 20nm diameter were synthesized by using a 90nm-thick layer of ZnO nanocrystals on the Si substrate as the seed layer. Both fabrication processes are repeatable and no catalysts are necessary. Finally, photoluminescence (PL) spectroscopy for ZnO nanowires using an He-Cd laser line of 325nm as the excitation source were measured at room temperature and both samples showed a sharp strong ultraviolet (UV) near-band edge emission. However, different UV peak positions (385nm for ZnO nanowire powder, 377nm for ZnO nanowire array) can be observed. The size confinement effect for excitons and carriers is proposed to explain the blue shift of the near-band edge emission with decreasing size and the native defects are responsible for the green emission.

We report the theory and experiments of a two-wavelength bi-tuning femtosecond Ti:sapphire laser. The cross-mode-locked gain competition is described with numerical solution and operation of the laser is accomplished in which two trains of femtosecond pulses cross in the Ti:sapphire rod. For this reason, a cross-bearings technique is used. The laser resonator is a six-mirror bi-cavity, and two beams of pump lights cross in Ti:sapphire crystal. Two trains of sub-30 fs cross-mode-locked pulses have been generated with independent tunable wavelength when the pump power of the argon laser is approximately 5 W. As the design of the bi-cavity is fine, not only strong gain competition is overcome, but also stable output characteristics are performed.

The experiment of the generation and amplification of femetosecond Ti:sapphire laser pulse at high repetition rate is reported. The laser pulses with minimum pulsewidth 15 fs, maximum spectrum width of 80 nm, average power of 200 mW are generated from a home-built self-mode-locked Ti:sapphire laser. As a seed pulse which is selected from the oscillator, the laser pulse is further amplified by using chirped-pulse-amplification technology in a Ti:sapphire amplifier from which a kind of pulses with single-pulse-energy of 100 uj, pulsewidth after compressing of 50 fs at 5 kHz repetition rate are produced. The system design and experimental results are discussed.

On the basis of self-stability effect of four-wave mixings (FWMs) in high-nonlinear photonic-crystal fibres, a novel multi-wavelength erbium-doped fibre (EDF) laser is proposed and demonstrated experimentally at room temperature. The proposed lasers have the capacity of switching and tuning with excellent uniformity and stability. By means of adjusting the attenuators, the triple-, four-, or five-wavelength EDF lasers can be lasing simultaneously. With the assistance of the FWM self-stability function, the multi-wavelength spectrum is excellently stabilized with uniformity less than 0.9 dB.

We report the generation of multi-wavelength visible light through amplified spontaneous emission (ASE) in Er3+-doped and Er3+/Yb3+-doped germanosilicate single-mode optical fiber pumped by a Nd:YLF laser at 1313 nm. In the Er3+-doped fiber, the intense multi-wavelength blue emission Lines around 463-510 nm correspond to transitions from 2G(7/2) etc. excited states to the melastable I-4(13/2) state, and their pumping mechanism is accomplished by a stepwise four-photon absorption. Some emission lines in this wavelength region are attributed to the three-wave sum-frequency process of 1313 and 1530 nm (corresponds to I-4(13/2)-I-4(15/2)). The intense green emission Lines at 525 and 540 nm are also observed in the Er3+-doped fiber. Ln the Er3+/Yb3+-doped fiber the blue and green lines are very weak compared with those in the Er3+-doped fiber.

We report a new first-order polarization-mode-dispersion (PMD) compensator based on birefringent crystals and magneto-optic polarization controllers. The compensator shows the response time of 150 μs, insertion loss smaller than 3 dB, and maximum differential group delay of 44.6 ps. Compared to the first-order PMD compensators reported so far, our PMD compensator exhibits fast response time, low insertion loss, compact size, broad bandwidth, and immunity to environmental vibrations.

To assess the effect of Klotho gene transduction on the progression of hypertension and heart damage in spontaneous hypertensive rats (SHRs).An adeno-associated virus (AAV) carrying full-length mouse Klotho cDNA (rAAV.mKL) was constructed for in vivo expression of Klotho. Three different groups of male SHRs and a control group of sex and age-matched Sprague Dawley (SD) rats (5 rats per group) were used. The experimental groups of SHRs received an IV injection of phosphate buffered saline (PBS), rAAV.mKL and rAAV.EGFP, respectively. The control group only received equal-volume of PBS. The whole study has spanned 12 weeks. Plasma levels of insulin-like growth factor-1 (IGF-1) and insulin were measured with ELISA. The weight of whole heart was measured to calculate the heart weight index (HWI). EGFP expression of heart frozen sections was observed by fluorescence microscopy. Expression of mRNA and protein of Klotho, IGF-1, IGF-1 receptor (IGF-1R) and p-Akt were determined with RT-PCR, immunohistochemical analysis, and Western blotting. Hypertrophic myocardial cell and collagen fiber were observed by histological examination following Haematoxylin-Eosin and Masson staining.Transduction of rAAV.mKL can significantly prevent the increase of blood pressure in SHRs. Compared with the control group, the levels of Klotho mRNA and protein have both increased, and the plasma levels of IGF-1, insulin and glucose were elevated, whereas the expression of phosphor-Akt (also called Protein Kinase B, PKB) was decreased in the rAAV.mKL group. Furthermore, a decrease of hypertrophic myocardial cells and collagen fibers was noticed in the rAAV.mKL group compared with the control group.The Klotho gene can attenuate the progression of hypertension and abolishes myocardial hypertrophy and myocardial fibrosis. The protective effect observed in the rAAV.mKL group of SHRs may be attributed to increased Klotho protein and suppression of insulin and IGF-1 signaling pathways through inhibition of Akt phosphorylation.

The physics-based methods that can effectively improve the image contrast in turbid media while truly preserving all the detailed information, have received great attention in recent years. The range-gated imaging (RGI), polarization difference method (PD) and polarization-based range-gated technology (PRG) are three effective methods of enhancing the contrast. However, the relationship between the extent of contrast enhancement and the imaging distance for each method has not been revealed. In this paper, a compact disc (CD) plate is set to be in the intralipid with different concentrations contained in a glass cell and imaged by RGI, PD, PRG and raw intensity imaging (RI). The Indian ink is used as the absorber which eliminates the multiple scattered photons and achieves the range-gated technology. In order to investigate the number of the scattered photons filtered out by the 4 methods, the image intensity curves are acquired while the imaging distance, the distance between the target surface and the front surface of the cell, is set to be 26 mm. The results indicate that PRG filters out the largest number of the scattered photons, followed by PD and RGI because the long imaging distance results in more multiple scattering photons. Then the influence of the imaging distance on the image intensity is investigated by the 4 methods. The image intensity is recorded while the imaging distance varies from 22 mm to 30 mm with even increments. Then four sets of intensity curves are plotted against the imaging distance corresponding to RI, RGI, PD and PRG respectively. Based on the RI, three sets of image intensity difference curves of RGI, PD and PRG are also calculated. The tendencies of the curves show that these imaging methods have their own imaging distance thresholds. It implies that the numbers of the photons filtered out by these methods are all constant when their imaging distances exceed their thresholds of 22 mm, 30 mm and 30 mm, respectively. Finally, the effect of the imaging distance on the contrast variation is studied in turbid media with two different scattering coefficient 0.714 cm-1 and 1.19 cm-1. The results show that PRG is superior to other methods in contrast enhancement. In addition, the imaging distances of the 4 methods under the same image contrast are obtained, showing that under the same contrast increment, the PRG presents the largest imaging distance enhancement, followed by PD, RGI and RI. The increase of scattering coefficient could also cause the decrease of the imaging distance. These results can be very useful to understand the mechanism of imaging in turbid media and are of great significance for improving the ability to recognize the target.

Channeled modulated polarimetry imaging (CMPI) is a novel detection technology which can acquire full-Stokes parameters of each pixel of the sensor. Compared with the other imaging polarimetric technologies, CMPI has advantages in compact, high spatial resolution and acquiring full-Stokes information simultaneously. It has been widely used in remote sensing, military reconnaissance and biomedical diagnosis. However CMPI can only be used for quasi-monochromatic light during full-Stokes imaging, which leads to low signal-to-noise ratio in many cases especially under the condition of low light. Expanding the imaging spectral bandwidth of the CMPI is of great urgency. In order to expand the bandwidth, the limitation factors and conditions of the imaging bandwidth should be clearly understood first. So an imaging bandwidth criterion is deduced in this paper for the researchers to estimate the limitation bandwidth of the CMPI. We analyze the factors which might affect the fringe visibility based on a Savart plate (SP) CMPI and obtain the conclusion that carry frequency (CF) is the main factor which restricts the bandwidth. Then, according to the definition of CF, = /(f), in which is the shearing distance of SP, is the imaging wavelength, and f the focal length of imaging lens, we investigate how these factors influence the CF. It turns out that is the main factor which causes the fringe to arise in a certain CPI system while would add an error to CF within 5% in visible light domain. To investigate how the wavelength influences the imaging spectral bandwidth, we deduce the total irradiance on the image plane under broadband light and use Fourier transform for it to obtain the distribution of the spatial frequency of the image plane. And the conclusion is obtained that the CF bandwidth be expressed as (20-1/(2L), 20 + 1/(2L)) referred to as the Rayleigh criterion, in which 0 is the central CF and L is the range of the imaging plane. After substituting the relevant parameters into the CF bandwidth, we can obtain the imaging spectral bandwidth criterion equation as = 2D02/(4D2-02) , in which is the maximum imaging bandwidth, D is the maximum optical path difference, and 0 is the central wavelength of the CMPI system. To validate the accuracy of the spectral bandwidth criterion, some simulations are conducted to generate a maximum imaging spectral bandwidth while the visibility of the fringes decreases to 0.5 for the fringes which cannot be distinguished when the visibility is less than 0.5. The results show that the error between the simulated spectral bandwidth and the calculated spectral bandwidth is less than 1 nm. This criterion value fits the test well for the SP CMPI system. In addition, it can also be used for estimating the maximum imaging bandwidth of the other CMPI system whose shearing distance is independent or quasi-independent of wavelength.

Direct-current transfer characteristics of (InGaN)/AlGaN/AlN/GaN heterojunction field effect transistors (HFETs) are presented. A drain current plateau (IDS = 32.0 mA/mm) for VGS swept from +0.7 V to −0.6 V is present in the transfer characteristics of InGaN/AlGaN/AlN/GaN HFETs. The theoretical calculation shows the coexistence of two-dimensional electron gas (2DEG) and two-dimensional hole gas (2DHG) in InGaN/AlGaN/AlN/GaN heterostructures, and the screening effect of 2DHG to the 2DEG in the conduction channel can explain this current plateau. Moreover, the current plateau shows the time-dependent behavior when IDS−VGS scans repeated are conducted. The obtained insight provides indication for the design in the fabrication of GaN-based super HFETs.

Although the first leading cause of death in China was malignant neoplasms (mortality, 374.1 per 100,000 person-years), the full impact of primary brain tumors (PBT) on the healthcare system is not completely described because there are a few well documented reports about the epidemiologic features of brain tumors. This study aimed to report a comprehensive assessment on the prevalence of PBT.A multicenter cross-sectional study on brain tumor (MCSBT) in China was initiated in five regional centers: Daqing (northeast), Puyang (north of China), Shiyan (center of China), Ma'anshan (center of China) and Shanghai (southeast). Prevalence rate was calculated by counting the number of people living with a PBT between October 1, 2005 and September 30, 2006 and dividing by the total population of the five communities at January 1, 2006. Estimates of prevalence were expressed as percentages and grouped according to gender and to age in fifteen-year categories. Within these strata, the rates were estimated with 95% confidence intervals (CI) using the accurate calculation of CI for Poisson distribution. A chi-square test was used to compare the various frequencies with α0.05. Age-standardized prevalence with the direct method was calculated with the ten-year age-specific prevalence and the age distribution of the Chinese population in 2010, obtained from World population prospects: the 2008 revision.We estimated that the overall prevalence of PBT was 24.56 per 100,000 (95%CI, 14.85 to 34.27), and the overall prevalence of PBT in female population (30.57 per 100,000 and its 95%CI ranged from 19.73 to 41.41) was higher than that in male population (18.84 per 100,000 and its 95%CI ranged from 10.33 to 27.35). However, the discrepancy between genders was not statistically significant because the 95%CI overlapped. Of 272 cases of newly diagnosed PBT, the proportion of histological subtypes by age groups, gender was statistically different (χ(2) = 52.6510, P0.0001). More than half of all reported tumors (52.57%) were either gliomas or meningiomas. For the youngest (aged from 0 - 19) strata of the population, glioma appeared to occur more than other subtypes, accounting for 55.56% of all of cases. The majority of brain tumors presented in those aged from 20 to 59 years was pituitary adenomas (45.12%) and gliomas (31.10%). Opposed to brain tumors in adults and teenage, gliomas only accounted for 22.22%. Meanwhile, the median ages at diagnosis of the patients with PBT were similar between males and females except for pituitary adenomas (male: 59 years old; female: 45 years old).Age standardized prevalence of PBT is 22.52 per 100,000 (95%CI, 13.22 to 31.82) for all populations, 17.64 per 100,000 (95%CI, 9.41 to 25.87) for men, and 27.94 per 100,000 (95%CI, 17.58 to 38.30) for women. Age standardization to China's 2010 population yielded an estimated population of 304 954 cases with PBT. Our prevalence estimates provide a conservative basis on which to plan health care services and to develop programmatic strategies for surviving. In the future, it would be helpful to have long-term observed survival rates that would make the assumptions and the resulting imprecision in the current estimates unnecessary.

Marked interindividual variation exists in blood pressure response to benazepril, which is considered to have genetic basis. Our objectives were to evaluate whether the E112D polymorphism in the prolylcarboxypeptidase (PRCP) gene has impact on blood pressure response to benazepril.Hypertensive patients from Huoqiu County and Yuexi County of Anhui Province received daily treatment with an oral dosage of 10 mg benazepril for 15 days. Genotypes of the E112D polymorphism in the PRCP gene were determined by TaqMan SNP genotyping assay. Multivariate linear and Logistic regressions using generalized estimating equation model were performed in a total of 1092 patients to evaluate the association of PRCP genotypes and blood pressure response to benazepril.Patients carrying ED or DD genotype had a less systolic blood pressure reduction (adjusted beta = -3.7 + or - 1.1, P0.001), a less diastolic blood pressure reduction (adjusted beta = -3.1 + or - 0.8, P0.001) and a lower percentage of reaching target blood pressure defined as SBP lower than 140 mmHg and DBP lower than 90 mmHg (adjusted OR = 0.6, P = 0.005) than those patients carrying EE genotype. In addition, the results from stratified analysis by county (Huoqiu or Yuexi) were similar to those observed in the pooled population.Our data suggest that the E112D polymorphism in the PRCP gene may be a useful genetic marker to predict the antihypertensive effect of short-term benazepril treatment in hypertensive patients of Anhui Province, China.

A thin oriented bacteriorhodopsin (bR) film is deposited on a stainless steel slide by the use of the electrophoretic sedimentation method. A junction is made with electrolyte gels having a counterelectrode to construct a bR-based photoelectric detector. The photoelectric response signal to a 10 ns laser pulse is measured. A theory on the photoelectric kinetics of bR is developed based on the concept of the charge displacement current and the bR photocycle rate equations. Comparison between the theoretical and experimental results proves that the bR photoelectric response to a short laser pulse is a multi-exponential process. The decay time constants and amplitudes of each exponential component are obtained by data fitting. PACS: 85. 60. Bt, 87. 15. Aa, 85. 65. +h

Poly (2-methoxy-5-octoxy-1, 4-phenylenevinylene) (MO-PPV) and functionalized multi-walled carbon tube (MO-PPV/MWNTs) composites with different MWNTs concentration were synthesized by in situ polymerization. The composites were characterized by AFM, PL spectra and UV-vis absorption spectra. The AFM phase image shows a good dispersion of MWNTs in the polymer matrix. PL and UV-vis spectra exhibited a blue shift of the main band.

Mirror-like surfaces of Al x Ga 1− x As/GaAs and Al x Ga 1− x As/GaAs/Al x Ga 1− x As/GaAs multi-layer structures with high aluminium content (ifx = 0.83) grown on semi-insulating GaAs substrates were obtained in a self-made atmospheric pressure MOCVD system. The thickness of the layers varied from several nm to 10 μm. The aluminium content ( x ) of the Al x Ga 1− x As layers could be controlled from 0 to 0.83. The high quality of the GaAs and Al x Ga 1− x As epilayers has been assessed from double crystal X-ray rocking curve measurements. A minority-carrier diffusion length of 4.02 μm for a Zn-doped GaAs epilayer ( N a = 2×10 19 cm −3 ) was obtained. High purity GaAs with n 300K = 1.7×10 15 cm −3 , μm 300K = 5900 cm 2 /V·s, n 77K = 1.4×10 15 cm and μm 77K = 55500 cm 2 /V⋯s has been obtained.

Based on the carrier continuity equation, the temporal response of field-assisted transmission-mode GaAs NEA photocathodes has been calculated. The results show that the response time of a common transmission-mode GaAs NEA photocathode can be decreased from about 1 ns to a few picosecond when an electric field is applied to it. The effective strength of the electric field for improving the response speed and the effect of the electric field on the response time over the whole response wavelength region of the photocathodes are also discussed in the paper.

Diagnostic measurement of single picosecond event in high energy density physics, laser fusion, plasma radiation, and combustion, is of great importance. However, the measuring of the shape of the single X-ray pulse and the synchronization of X-ray and the laser pulse in picosecond resolution is still a great challenge. Restricted by the transit time of electrons, the time-resolution limit of a conventional framing camera based on the microchannel plate is 40 ps. Centered on the full-optical modulation effect of the light-probe, a novel method for X-ray detection of picoseconds temporal resolution based on low temperature GaAs is proposed in this work. The basic physical mechanism of the detector can be explained in both macroscopical and microcosmic ways. In the macroscopical way, the X-ray radiation absorption in the sensor material produces a transient, non-equilibrium electron-hole pair distribution that results in a transient differential change of the local refractive index, which is then sensed by the reflectivity changes of the optical probe beam. In the microcosmic way, X-ray absorption creates photoelectrons and the core level holes are subsequently filled through Auger or fluorescence processes. These excitations ultimately increase conduction and valence band carriers that perturb optical reflectivity.#br#To verify the proposed X-ray detection method, a Fabry-Perot detector is designed, which consists of a 5 μm thick GaAs layer surrounded by a GaAs/AlAs distributed Bragg reflector. The test is carried out on a femtosecond laser facility, where the X-ray source is produced by focusing the 56 fs Ti: Sapphire facility laser, with a central wavelength of 800 nm, onto an aluminum foil. Then the X-ray pulse induces a transient optical reflectivity change in GaAs, which is a powerful tool for establishing the high-speed X-ray detection.#br#The experimental results indicate that this technology can be used to provide X-ray detectors with a temporal resolution of tens of picoseconds. By optimizing the material, the temporal resolution can be enhanced to be less than 1 ps. Through further development, this X-ray detector could provide an insight into previously unmeasurable phenomena in many fields. Future work will focus on developing much faster devices characterizing both the rise and fall time and imaging array technology.

To study the relationship between resting heart rate and single nucleotide polymorphisms (SNP) at 3 sites of nitric oxide synthase (NOS) gene including NOS3 -922A/G, NOS3 894G/T and NOS2 -1173C/T SNPs.Genomic DNA was gained from 211 Chinese Han nationality population. The SNPs of NOS3 -922A/G, NOS3 894G/T and NOS2 -1173C/T were genotyped by allele-specific primer-polymerase chain reaction (ASP-PCR) technique.The distribution frequencies of GG, GT and TT genotypes of NOS3 894G/T and AA, AG and GG genotypes of NOS3 -922A/G and CC, CT and TT genotypes of NOS2 -1173C/T were consistent with Hardy-Weinberg equilibrium (P0.05). The resting heart rate of Chinese Han nationality population with AA genotypes was higher than that with GG genotype of NOS3 -922A/G (P0.01). The resting heart rate of the sub-population with GG genotype was higher than that with TT genotype of NOS3 894G/T (P0.05). There were no difference among the resting heart rates of the sub-populations with the allele genotypes of NOS2 -1173C/T.The resting heart rate of Chinese Han nationality population with mutated genotype GG of NOS3 -922A/G and with mutated genotype TT of NOS3 894G/T were lower than those with wild genotype of NOS3 -922A/G and NOS3 894G/T. The finding suggests that resting heart rate is associated with SNP of NOS3 -922A/G and NOS3 894G/T.

To study single nucleotide polymorphisms (SNP) in A-922G, T-786C and G894T of endothelial nitric oxide synthase (NOS3) and to correlate the distribution of their allelic combinations with hypertension in Chinese Han nationality population, genomic DNA was isolated from venous blood leukocytes from 192 unrelated patients with hypertension (95 females and 97 males) and 122 healthy unrelated individuals (46 females and 76 males) as controls. SNPs of NOS3 A-922G, T-786C and G894T were genotyped by allele-specific primer (ASP) PCR. The distribution of genotype combinations of three SNPs was determined by clustering analysis. There were no difference in allele genotype distribution frequency and haplotype frequency of NOS3 G894T, NOS3 A-922G and NOS3 T-786C between the essential hypertension group and the healthy population (P0.05). According to sex stratification, no association between essential hypertension and SNP of NOS3 A-922G,NOS3 T-786C or NOS3 G894T has been found in either the male subgroup or the female subgroup. In respect of allele genotype combination frequency in the natural distribution of NOS3 A-922 G, NOS3 T-786C and NOS3 G894T SNP, there was significant difference only in the allele genotype combination frequency of NOS3 G894G+A-922G+T-786T between the hypertension group and the healthy group (P0.05, Chi2=4.5944). According to sex stratification, there were no significant difference in all above allele genotype combination frequency in three sites of NOS3 SNP between the hypertension male subgroup and the healthy male subgroup (P0.05). There was significant difference in the allele combination frequency of NOS3 G894G +A-922G+T-786C between the hypertension female subgroup and the healthy female subgroup(P001, Chi2=8.502). There was no association of SNP in NOS3 A-922G, NOS3 T-786C or NOS3 G894T with hypertension in the Chinese Han nationality population, nor was there a sex difference. The combination frequency of allele NOS3 G894G + A-922G + T-786C in the hypertension female subgroup was much lower than that in the healthy female subgroup, suggesting that female population with this combination genotype may be less susceptible to hypertension.

We investigated associations of the Gly460Trp polymorphism of the alpha-adducin gene and concentrations of serum total bilirubin, serum direct bilirubin and serum unconjugated bilirubin in patients with essential hypertension from Anhui, China from September 2000 to January 2001. Compared to women with the Gly/Gly genotype and after adjustment for important covariates, women with the Trp/Trp genotype had lower mean concentrations of serum total bilirubin (beta = -1.2 micromol/L; P = 0.01), serum direct bilirubin (beta = - 0.4 micromol/L; P = 0.02) and serum unconjugated bilirubin (P = -0.8 micromol/L; P = 0.03). Among women in either the upper or lower quartiles of serum total bilirubin, serum direct bilirubin and serum unconjugated bilirubin and compared to those with the Gly/Gly genotype, women with the Trp/Trp genotype had higher odds of being in the lower quartile of concentrations of serum total bilirubin (odds ratio = 4.0; 95 percent confidence interval: 1.6 - 10.2; P0.01), serum direct bilirubin (odds ratio = 4.0; 95 percent confidence: 1.6 - 9.7; P0.01) and serum unconjugated bilirubin (odds ratio = 2.7; 95 percent confidence interval: 1.1 - 6.7; P = 0.03) after adjustment for important covariates. We did not observe any significant associations in these models for men. We concluded that the Trp/Trp genotype of alpha-adducin Gly460Trp was associated with lower serum bilirubin concentrations in this group of Chinese women with essential hypertension. Women with the Trp/Trp genotype of alpha-adducin Gly460Trp might have increased risk for cardiovascular diseases due to lower concentrations of serum bilirubin.

We numerically calculate the wave function of two-dimensional electron gas (2DEG) for use in 2DEG transport theory and study the electron transport in ZnMgO/ZnO heterostructures. For strongly confined 2DEG, the temperature dependence of the electron mobility is satisfactorily explained using 2DEG transport theory. The interface roughness and ionized impurity scatterings play important roles in the electron transport at low and moderate temperatures. At room temperatures polar optical phonon scattering is the most important scattering mechanism. For heterostructures having two parallel conduction paths in the 2DEG at the ZnMgO/ZnO interface and in the ZnO thick layer, the electron transport is contributed by the two paths. We calculate the mobility for the respective conduction paths, and then combine the two mobility components to fit the experimental data. The theoretical calculations are in good agreement with the experimental data.

A simple method using an 800-nm femtosecond laser and chemical selective etching is developed for fabrication of high-aspect-ratio grooves in silicon carbide. Micro grooves with an aspect ratio of approximately 40 are obtained. The morphology and chemical compositions of the grooves are analyzed using a scanning electronic microscope equipped with an energy dispersive x-ray spectroscopy. The formation mechanism of SiC grooves is attributed to the chemical reactions of the laser induced structural changes with a mixed solution of hydrofluoric acid and nitric acid. In addition, the effects of laser irradiation parameters on the aspect ratio of the grooves are investigated. Due to its small size, excellent performance, low cost and high volume production, microelectromechanical systems (MEMSs) have attracted increasing attention of researchers. Silicon-based MEMS devices have been well developed. These devices are generally limited in electronic devices performance to below 250 ∘ C, and in mechanical device performance to below 600 ∘ C. They are not suitable working in the cor