Raman soliton at 2 μm in picosecond pumped supercontinuum by a weak CW trigger

Injecting a weak narrow-linewidth CW trigger to control the picosecond pulse pumped supercontinuum (SC) generation in a highly nonlinear dispersion shifted fiber (HNL-DSF), the Raman soliton at 2 μm is experimentally observed. We demonstrate that the cascaded four-wave mixing (FWM) caused by the weak CW trigger accelerates soliton fission and collision, and the large red-shift by the Raman effect in fibers induces obvious Raman soliton occurring in the long wavelength range of SC. A reduced effect on spectral modification on the SC spectrum at higher pump powers is also observed in the experiment. Simulations of the spectral evolution and spectrogram are carried out to verify the experimental observation. Both experiment and simulation results show the SC characteristics in the mid-infrared region can be greatly improved by the triggering effect.

[Construction and mechanical analysis of finite element model for bending property of controlled memory wire nickel-titanium rotary file]

OBJECTIVE

To construct a model for a controlled memory (CM) nickel-titanium (NiTi) file and another M-wire NiTi file with the same geometry by using finite element analysis. To evaluate the flexibility of a CM NiTi file by using three dimensional finite element method and to compare its mechanical responses with that M-wire NiTi.

METHODS

Based on the reverse engineering, the 21 mm long, 25#/08 taper Hyflex NT NiTi file and Hyflex CM NiTi file were fixed by the cantilever bending model at a distance of 9.5 mm from the tip of the file. The mechanical tester's indenter was loaded/unloaded at a distance of 3 mm from the tip of the file. The maximum displacement was 3 mm, the load displacement curve was obtained. Subsequently, by using a micro-CT to scan (layer spacing of 8 μm) NiTi files, and ABAQUS (6.10) was introduced to construct a geometric model. Hyflex NT was considered as a shapememory alloy constitutive model, Hyflex CM was considered as a power-hardening plastic constitutive model, respectively. Comparing the load-displacement curve of cantilever bending in the three-dimensional finite element model with the load-displacement curve in the experiment.

RESULTS

Two tetrahedral element models were constructed, the total number of nodes was 99 353 and the total number of cells was 63 744. When the loading displacement was 1 mm, the stress distribution of the cross section at 6.1 mm from the tip of the file was observed. The upper and lower surfaces were subjected to the maximum bending stress and entered the phase transformation yield stage. The finite element simulation could clearly show the deformation of the file. Various information such as deformation characteristics and stress distribution in the process were well fitted to the actual experimental curve.

CONCLUSION

The constitutive behavior of the material has a significant effect on the mechanical behavior of NiTi file. The finite element model established for the NiTi file of the CM wire can accurately capture the characteristics of various deformation processes of the NiTi root canal file, and it has a good fit with the actual experimental curve. The finite element model can be used for study on bending properties of CM wire.

[Clinical significance of hypermethylation of DLC-1 gene in myelodysplastic syndrome patients and effects of decitabine on DLC-1 gene expression]

Objective: To detect the methylation status of DLC-1 gene in the patients with myelodysplastic syndrome(MDS), the effect of abnormal methylation of DLC-1 gene on the expression of DLC-1 gene, the clinical significance of methylation of DLC-1 gene in MDS patients, and the effect of decitabine on DLC-1 gene expression. Methods: A total of 43 MDS patients were treated in Fujian Medical University Union Hospital from 2013 to 2015. Methylation status of DLC-1 gene in MDS patients were detected by the methylation specific PCR(MSP). The expression of DLC-1 gene mRNA was determined with real-time fluorescence quantitative PCR(RTFQ-PCR). MDS patients were divided into 5 groups (very low-risk, low-risk, intermediate-risk, high-risk and very high-risk, n=0, 8, 7, 18, 10) according to WPSS classification. And the clinical significance of methylation of DLC-1 gene in patients with MDS were investigated. In order to investigate the change in gene methylation and expression of DLC-1 gene after treatment with decitabine, methylation statuses of DLC-1 gene in MDS patients before and after be treated with decitabine were detected by the bisulfite sequencing PCR(BSP). The expressions of DLC-1 gene mRNA of these patients were determined with RTFQ-PCR. Results: Hypermethylation of CpG island of DLC-1 gene was observed in 55.16%(22/43)MDS patients. The expressions of DLC-1 gene mRNA in methylation positive patients were significantly lower than that in methylation negative patients (0.32±0.06 vs 0.91±0.11)(P=0.008). For MDS patients, the DLC-1 methylation rate of intermediate-and high-risk patient was 21/35, which was significantly higher than that of low-risk patient(1/8, P=0.006). The methylation status of DLC-1 gene were monitored in 8 patients before and after treatment with the decitabine (decitabine 20 mg/m(2,) d1-d5/d28, more than 4 courses) , the methylation rate of DLC-1 gene dropped from 57.50%±5.11% to 14.13%±2.07% after treatment(P=0.010). The expression of DLC-1 gene increased after treatment with decitabine(0.67±0.08 vs 0.28±0.06, P=0.015). Conclusions: Methylation of DLC-1 gene is common in MDS patients and may be associated with poor prognosis. Decitabine may activate the expression of DLC-1 gene by demethylation, which may be one of the mechanisms for the treatment of patients with MDS.

Linkage analysis of SNPs in IGFBP-6 and its relation with the body sizes of pig

Insulin-like growth factor binding protein-6 (IGFBP-6) is a member of the IGFBP family, which is known to be a key factor in regulating the effect of insulin-like growth factor-2 (IGF-2) on the animal growth and development. Gene sequences of 3'-untranslated regions (UTR) and exon 4 of IGFBP-6 may influence the expression and proteolysis of IGFBP-6. In this study, 551 bp of the IGFBP-6 (including 257 bp of intron 3, exon 4, and 170 bp of 3' UTR) were sequenced and compared in the Bama and Tibetan mini-pigs, the Landrace and Large White pigs, and the Northeast wild boars. Six single nucleotide polymorphisms (SNPs) were detected in the IGFBP-6, in which T593C, T636C, and T745C were in intron 3, A67G was in exon 4, and G37A was in 3' UTR. T636C, T745C, and A67G were in linkage and formed four kinds of haplotypes, with CCT being the dominant haplotype in the mini-pigs; however, the haplotype block was not formed in the Landrace pigs and Large White pigs or the Northeast wild boars. Based on the above results, we concluded that the SNPs and haplotype of the IGFBP-6 may be related to the mini-size formation of the pig.

Oral Helicobacter pylori, its relationship to successful eradication of gastric H. pylori and saliva culture confirmation

The present study was designed to explore the existence of oral Helicobacter pylori (H. pylori), its relationship in the oral cavity to the success rate of eradication of the gastric H. pylori infection, and to determine if the mouthwash solution contained lysine (0.4%) and glycerol monolaurate (0.2%) (LGM) could eliminate oral H. pylori, as well as using the saliva H. pylori culture to confirm the existence of oral H. pylori. A total of 159 symptomatic individuals with stomach pain and 118 asymptomatic individuals with no stomach complaints, were recruited and tested using the saliva H. pylori antigen test (HPS), the H. pylori flagellin test (HPF), the urea breath test (UBT C(13)) and the polymerase chain reaction (PCR) test, which tests were also confirmed by saliva culture. The test subjects also received various treatments. It was found that the H. pylori antigen exists in the oral cavity in UBT C(13) negative individuals. Traditional treatment for gastric eradication had only a 10.67 percent (10.67%) effectiveness rate on the oral H. pylori infection. In groups of patients with the oral H. pylori infection, but with negative UBT C(13), a mouthwash solution provided a 72.58% effectiveness rate in the 95% of the confidence interval (CI) ranges on the oral H. pylori infection. Traditional drug gastric eradication and teeth cleaning (TC) had less than a 10% effectiveness rate. Treatment of the oral infection increased the success rate of eradication of the stomach infection from 61.33% to 82.26% in the 95% CI ranges. We concluded that the successful rate of eradication of gastric H. pylori bears a significant relationship to the oral infection from H. pylori.

Raman fiber laser harmonically mode-locked by exploiting the intermodal beating of CW multimode pump source

We report here the first demonstration of a harmonic mode-locked Raman fiber laser using the intermodal beating of a continuous-wave (CW) multiple-longitudinal-mode pump laser. By matching the Raman-cavity round-trip frequency with the intermodal-beating one of a 1064 nm CW pump source, harmonic mode-locking in phosphosilicate Raman fiber laser is stably initiated at the first-order Stokes of 1239.5 nm, and generates rectangular-shape nanosecond pulses with the pulse energy up to 4.25 nJ. Using the new type of mode-locking, the harmonic order can be discretely tuned from 78 th- to 693 rd-order, and the cavity supermode is suppressed up to 51.1 dB with the signal-to-noise ratio of more than 65 dB.

Molecular dynamics simulation of the interfacial structure of [C(n)mim][PF6] adsorbed on a graphite surface: effects of temperature and alkyl chain length

The structures and diffusion behaviors of a series of ionic liquids [C(n)mim][PF(6)] (n = 1, 4, 8 and 12) on a graphite surface have been investigated by means of molecular dynamics simulation. It was found that three or four ordering layers of ionic liquids were formed near the graphite surface, and this layering structure was stable over the temperature range investigated. At the liquid/vacuum interface, the ionic liquid with a butyl chain had a monolayer ordering surface, while [C(8)mim][PF(6)] and [C(12)mim][PF(6)] exhibited a bilayer ordering with a polar domain sandwiched between two orientational nonpolar domains. More impressively, the simulated results showed that for the ionic liquids with alkyl chains longer than C(4), the adjacent alkyl chains in the whole film tended to be parallel to each other, with the imidazolium rings packed closely together. This indicated that the ionic liquids have a better regulated short-range structure than was previously expected. It was also found that both in the bottom layer and in the bulk region, the diffusion of the alkyl chains was much faster than that of the polar groups. However, as the alkyl chain length increased, the charge delocalization in the cation and the enhanced van der Waals interaction between the nonpolar groups contributed by reducing this difference in the diffusivity of major groups.

High-pressure and high-temperature characteristics of a Fabry-Perot interferometer based on photonic crystal fiber

A fiber-optic Fabry-Perot interferometer was constructed by splicing a short length of photonic crystal fiber to a standard single-mode fiber. The photonic crystal fiber functions as a Fabry-Perot cavity and serves as a direct sensing probe without any additional components. Its pressure and temperature responses in the range of 0-40 MPa and 25°C-700°C were experimentally studied. The proposed sensor is easy to fabricate, potentially low-cost, and compact in size, which makes it very attractive for high-pressure and high-temperature sensing applications.

Fourier analysis for hydrostatic pressure sensing in a polarization-maintaining photonic crystal fiber

We measured the hydrostatic pressure dependence of the birefringence and birefringent dispersion of a Sagnac interferometric sensor incorporating a length of highly birefringent photonic crystal fiber using Fourier analysis. Sensitivity of both the phase and chirp spectra to hydrostatic pressure is demonstrated. Using this analysis, phase-based measurements showed a good linearity with an effective sensitivity of 9.45 nm/MPa and an accuracy of ±7.8 kPa using wavelength-encoded data and an effective sensitivity of -55.7 cm(-1)/MPa and an accuracy of ±4.4 kPa using wavenumber-encoded data. Chirp-based measurements, though nonlinear in response, showed an improvement in accuracy at certain pressure ranges with an accuracy of ±5.5 kPa for the full range of measured pressures using wavelength-encoded data and dropping to within ±2.5 kPa in the range of 0.17 to 0.4 MPa using wavenumber-encoded data. Improvements of the accuracy demonstrated the usefulness of implementing chirp-based analysis for sensing purposes.

Multiplexing of polarization-maintaining photonic crystal fiber based Sagnac interferometric sensors

Three multiplexing schemes are presented for polarization-maintaining photonic crystal fiber based Sagnac interferometric sensors. The first technique is wavelength division multiplexing using coarse wavelength division multiplexers (CWDMs) to distinguish signals from each multiplexed sensor in different wavelength channels. The other two schemes are to multiplex sensors in series along a single fiber link and in parallel by using fiber-optic couplers. While for the CWDM scheme, the multiplexed sensing signal can be obtained by direct measurement; for the other two multiplexing techniques, the sensing signal is more complex and cannot be easily demultiplexed. Thus, some signal processing methods are required. In this regard, two mathematical transformations, namely the discrete wavelet transform and Fourier transform, have been independently and successfully implemented into these two schemes. The operating principles, experimental setup, and overall performance are discussed.

Pressure sensor realized with polarization-maintaining photonic crystal fiber-based Sagnac interferometer

A novel intrinsic fiber optic pressure sensor realized with a polarization-maintaining photonic crystal fiber (PM-PCF) based Sagnac interferometer is proposed and demonstrated experimentally. A large wavelength-pressure coefficient of 3.42 nm/MPa was measured using a 58.4 cm long PM-PCF as the sensing element. Owing to the inherently low bending loss and thermal dependence of the PM-PCF, the proposed pressure sensor is very compact and exhibits low temperature sensitivity.

Intensity-modulated fiber Bragg grating sensor system based on radio-frequency signal measurement

An intensity-modulated, fiber Bragg grating (FBG) sensor system based on radio-frequency (RF) signal measurement is presented. The RF signal is generated at a photodetector by two modulated optical signals reflected from the sensing FBG and a reference FBG. Wavelength shift of the sensing FBG changes intensity of the RF signal through changing the delay between the two optical signals, with temperature effect being compensated automatically by the reference FBG. It also exhibits important features including potentially high-speed measurement, low cost, and adjustable sensitivity. In the experiment, strain measurement with a maximum sensitivity of -0.34 microV/micro epsilon has been achieved.

Observation of two new N* peaks in J/psi-->ppi-n and ppi+n decays

The decay J/psi-->NNpi provides an effective isospin 1/2 filter for the piN system due to isospin conservation. Using 58x10(6) J/psi decays collected with the Beijing Electromagnetic Spectrometer at the Beijing Electron Positron Collider, more than 100 thousand J/psi-->ppi-n+c.c. events are obtained. Besides the two well-known N* peaks at around 1500 MeV/c2 and 1670 MeV/c2, there are two new, clear N* peaks in the ppi invariant mass spectrum around 1360 MeV/c2 and 2030 MeV/c2 with statistical significance of 11sigma and 13sigma, respectively. We identify these as the first direct observation of the N*(1440) peak and a long-sought missing N* peak above 2 GeV/c2 in the piN invariant mass spectrum.

Observation of a threshold enhancement in the plambda invariant-mass spectrum

An enhancement near the m(p)+M(Lambda) mass threshold is observed in the combined pLambda and pLambda invariant-mass spectrum from J/psi-->pK(-)Lambda;+c.c. decays. It can be fit with an S-wave Breit-Wigner resonance with a mass m=2075+/-12(stat)+/-5(syst) MeV and a width of Gamma=90+/-35(stat)+/-9(syst) MeV; it can also be fit with a P-wave Breit-Wigner resonance. Evidence for a similar enhancement is also observed in psi(')-->pK(-)Lambda;+c.c. decays. The analysis is based on samples of 5.8x10(7)J/psi and 1.4x10(7)psi(') decays accumulated in the BES II detector at the Beijing Electron-Positron Collider.

Helicobacter bilis infection in biliary tract cancer

BACKGROUND

Biliary tract cancer is a highly fatal disease with poor prognosis, but the aetiology is poorly understood.

AIM

We aimed to identify Helicobacter bilis infection in the gallbladder in patients with biliary tract disease.

METHODS

Archival gallbladder specimens from 34 patients (14 males and 20 females) with an average age of 61.4 +/- 12.2 years (mean +/- SE) were retrieved, consisting of 11 cases of gallbladder cancer, three of bile duct cancer, 16 of cholecystolithiasis and four of pancreatic cancer. DNA was extracted and nested PCR using primers specific for 16S rRNA of H. bilis was performed.

RESULTS

Amplification was observed in 3 of 11 gallbladder cancer cases (27.2%) and one of three cases with biliary duct cancer (33.3%). In total, four of 14 cases with biliary tract cancer were positive for H. bilis (28.6%). In addition, the presence of H. bilis was shown in two of 16 cases (12.5%) with cholecystolithiasis. Notably, although the number of cases examined was small, none of the four cases with pancreatic cancer showed the presence of H. bilis infection in the gallbladder without apparent abnormalities.

CONCLUSION

H. bilis infection may play a role in biliary tract disease, particularly in biliary tract cancer.

Observation of the decay psi(2S)-->K0SK0L

The decay psi(2S)-->K(0)(S)K(0)(L) is observed using psi(2S) data collected with the Beijing Spectrometer at the Beijing Electron-Positron Collider; the branching fraction is determined to be B(psi(2S)-->K(0)(S)K(0)(L))=(5.24+/-0.47+/-0.48)x10(-5). Compared with J/psi-->K(0)(S)K(0)(L), the psi(2S) branching fraction is enhanced relative to the prediction of the perturbative QCD "12%" rule. The result, together with the branching fractions of psi(2S) decays to other pseudoscalar meson pairs (pi(+)pi(-) and K+K-), is used to investigate the relative phase between the three-gluon and the one-photon annihilation amplitudes of psi(2S) decays.

Observation of a near-threshold enhancement in the pp mass spectrum from radiative J/psi-->gammapp decays

We observe a narrow enhancement near 2m(p) in the invariant mass spectrum of pp pairs from radiative J/psi-->gammapp decays. No similar structure is seen in J/psi-->pi(0)pp decays. The results are based on an analysis of a 58 x 10(6) event sample of J/psi decays accumulated with the BESII detector at the Beijing electron-positron collider. The enhancement can be fit with either an S- or P-wave Breit-Wigner resonance function. In the case of the S-wave fit, the peak mass is below 2m(p) at M=1859(+3)(-10) (stat)+5-25(syst) MeV/c(2) and the total width is Gamma<30 MeV/c(2) at the 90% confidence level. These mass and width values are not consistent with the properties of any known particle.

Measurements of the cross section for e(+)e(-) --> hadrons at center-of-mass energies from 2 to 5 GeV

We report values of R = sigma(e(+)e(-)-->hadrons)/sigma(e(+)e(-)-->mu(+)mu(-)) for 85 center-of-mass energies between 2 and 5 GeV measured with the upgraded Beijing Spectrometer at the Beijing Electron-Positron Collider.

[Mechanism of decoction of guizhi tang on dual-directional thermoregulation. Effect on the action of bombesin]

Hypothermia induced by administration of bombesin into the lateral ventricle of brain in cold exposed rats could be inhibited by Guizhi Tang (GZT). The GZT could also reverse the potency of fever induced by injection of [D-Phe12] bombesin, a bombesin receptor antagonist, into the brain of febrile rats. But there was no effect of GZT on body temperature when bombesin and [D-Phe12] bombesin were simultaneously injected into the lateral ventricle of cold exposed rats. These studies indicated that the dual-directional thermoregulation of GZT was carried out partially by affecting the bombesin receptor in thermoregulation center of hypothalamus.

[Mechanism of guizhi tang on dual-directional thermoregulation--effect of prostaglandin E2 level in hypothalamus of rats]

Antipyretic action was found in febrile rats induced by yeast, and body temperature was elevated in hypothermia rats induced by aminopyrine, when 10 g/kg of Guizhi Tang (GZT) was administered per os. The content of prostaglandin E in the hypothalamus of rats was determined with the radioimmunoassay. Administration of GZT in 10 g/kg p.o. could both decrease the PGE2 level of hypothalamic blood in febrile rats, and increase the PGE2 level in hypothermia rats. Antipyretic action of GZT was also displayed when microinjection of PGE2 into the lateral ventricle which produced fever in rats. The evidence was provided that GZT might carry out at least part of the dual-directional regulating action in body temperature through the promotion or inhibition on PGE2 synthesis, release, or metabolism in the thermoregulatory center.

[Distribution of serotypes and biotypes of Campylobacter jejuni/coli strains from ten provinces/cities in China]

The Lior's schemes were used for serotyping and biotyping 301 C. jejuni/coli strains isolated from different hosts in ten provinces/cities of China. No difference was found between the serotype distributions of the strains isolated from various areas. Forty-one serotypes were detected. Of the isolates, 86.71% were typable and 3 new serotypes, LIO N-1, N-2 and N-3, were developed. The differences were proved among the serotype distributions of the isolates from different areas. It was shown that one host could be infected by two (or more) strains belonging to different serotypes at the same time. No association between a particular biotype and serotype was observed.

[Studies on the hidropoiesis of the decoction of gui-zhi tang in mice and rats]

Effects of the Decoction of Gui Zhi Tang (DGZT) on the hidropoiesis of animal paw in different pathophysiological conditions were studied with the examination of sweat stains. The diaphoresis was found in normal rats when 2.5-10.0 g crude drugs/kg p.o. of the DGZT was administrated. The diaphoretic function was also promoted by DGZT in mice infected with influenza virus which the function was gradually suppressed. The decoction had the action of bidirectional regulation and normalization in polyhidrosis induced by aminopyrine or in hypohidrosis induced by atropine on rats.