Fresh hetero-metallic compound as luminescent sensor for detection of CS2 and inhibitory activity on children diabetes.

The combination of the dicarboxylate ligand of 2-aminoterephthalic acid (H2L), Cd(NO3)2·4H2O, and KNO3 under hydrothermal condition formed a fresh hetero-metallic coordination polymer, namely, [CdK2(L)2(H2O)4]n (1). The compound exhibited a high luminescence intensity at normal environment as well as high sensitivity and selectivity in the measurement of CS2. The effect of the fresh compound on childhood diabetes was investigated. A blood glucose monitor was utilized to assess the blood glucose level of the body after the addition of the compound. Moreover, the relative expression level of the insulin recipient on hepatocytes was assessed by real time RT-PCR.

Photoredox-catalyzed redox-neutral difluoroalkylation to construct perfluoroketones with difluoroenoxysilanes.

A mild and facile approach to construct various perfluoroketones via photo-catalyzed difluoroalkylation of difluoroenoxysilanes is developed. The reaction includes a strategy of combination of two fluorine-containing functional groups, which confers the reaction with characteristics like high efficiency, mild conditions, and broad scope. A variety of fluoroalkyl halides including perfluoroalkyl iodides, bromo difluoro esters and amides can be employed as radical precursors. Control experiments indicate that a single-electron transfer pathway may be involved in the reaction.

Photonic-assisted microwave phase shifter using a DMZM and an optical bandpass filter.

We propose and demonstrate a photonic-assisted wideband 360° microwave phase shifter based on a conventional dual-drive Mach-Zehnder modulator (DMZM) and an optical bandpass filter (OBPF). The two arms of the DMZM are driven by the fundamental microwave signal to be phase shifted and its frequency doubled component, respectively. The OBPF followed after the DMZM is used to remove the optical carrier and the sidebands at either side of the optical carrier. As a result, only two sidebands corresponding to the fundamental microwave signal and its frequency doubled component, respectively, are left. Moreover, the phase shift between the two sidebands can be continuously tunable by adjusting the bias voltage of the DMZM. This phase shift is mapped to the fundamental microwave signal which is recovered by beating the two sidebands in a photodetector (PD). The proposed approach is theoretically analyzed and experimentally verified.

Generation of triangular waveforms based on a microwave photonic filter with negative coefficient.

We report a novel approach to generating full-duty-cycle triangular waveforms based on a microwave photonic filter (MPF) with negative coefficient. It is known that the Fourier series expansion of a triangular waveform has only odd-order harmonics. In this work, the undesired even-order harmonics are suppressed by the MPF that has a periodic transmission response. A triangular waveform at fundamental frequency can be generated by setting the bias of a Mach-Zehnder modulator (MZM) at quadrature point. However, it is found that a broadband 90° microwave phase shifter has to be used after photodetection to adjust the phases of odd-order harmonics. Alternatively, a frequency doubling triangular waveform can be generated by setting the bias of the MZM at maximum or minimum transmission point. This approach is more promising because the broadband microwave phase shifter is no longer required in this case but it is more power consuming. The proposed approach is theoretically analyzed and experimentally verified.

Generation of FCC-compliant and background-free millimeter-wave ultrawideband signal based on nonlinear polarization rotation in a highly nonlinear fiber.

We propose a novel approach to generating millimeter-wave (MMW) ultrawideband (UWB) signal based on nonlinear polarization rotation (NPR) in a highly nonlinear fiber (HNLF). The MMW UWB signal is background-free by eliminating the baseband frequency components using an optical filter. The proposed scheme is theoretically analyzed and experimentally verified. The generated MMW UWB signal centered at 25.5 GHz has a 10-dB bandwidth of 7 GHz from 22 to 29 GHz, which fully satisfies the spectral mask regulated by the Federal Communications Commission (FCC).

Photonic generation of arbitrarily phase-modulated microwave signals based on a single DDMZM.

We propose and demonstrate a compact and cost-effective photonic approach to generate arbitrarily phase-modulated microwave signals using a conventional dual-drive Mach-Zehnder modulator (DDMZM). One arm (arm1) of the DDMZM is driven by a sinusoidal microwave signal whose power is optimized to suppress the optical carrier, while the other arm (arm2) of the DDMZM is driven by a coding signal. In this way, the phase-modulated optical carrier from the arm2 and the sidebands from the arm1 are combined together at the output of the DDMZM. Binary phase-coded microwave pulses which are free from the baseband frequency components can be generated when the coding signal is a three-level signal. In this case, the precise π phase shift of the microwave signal is independent of the amplitude of the coding signal. Moreover, arbitrarily phase-modulated microwave signals can be generated when an optical bandpass filter is attached after the DDMZM to achieve optical single-sideband modulation. The proposed approach is theoretically analyzed and experimentally verified. The binary phase-coded microwave pulses, quaternary phase-coded microwave signal, and linearly frequency-chirped microwave signal are experimentally generated. The simulated and the experimental results agree very well with each other.

Widely tunable single bandpass microwave photonic filter based on Brillouin-assisted optical carrier recovery.

A widely tunable single bandpass microwave photonic filter (MPF) based on Brillouin-assisted optical carrier recovery in a highly nonlinear fiber (HNLF) with only one optical filter is proposed and experimentally demonstrated. The fundamental principle lies in the fact that the suppressed optical carrier of the phase modulated optical signal could be recovered by the stimulated Brillouin scattering (SBS) amplification effect. When phase modulated optical signals go through an optical filter with a bandpass response, the optical carrier and the upper sidebands suffer from the suppression of the optical filter because they fall in the stopband of that. In our system, the optical carrier could be recovered by the SBS operation around 38 dB. The MPF is achieved by one-to-one mapping from the optical domain to the electrical domain only when one of phase modulated sidebands lies in the bandpass of the optical filter. It shows an excellent selectivity with a 3-dB bandwidth of 170 MHz over a tuning frequency range of 9.5-32.5 GHz. The out-of-band suppression of the MPF is more than 20 dB. Moreover, the MPF shows an excellent shape factor with 10-dB bandwidth of only 520 MHz. The frequency response of the MPF could be widely tuned by changing the frequency difference between the frequency of the optical carrier and the center frequency of the bandpass of the optical filter. A proof-of-concept experiment is carried out to verify the proposed approach.

Optically controlled microwave phase shifter based on nonlinear polarization rotation in a highly nonlinear fiber.

This Letter reports an optically controlled microwave phase shifter with an ultra-wideband working bandwidth and a full 360° phase shifting range based on nonlinear polarization rotation (NPR) in a highly nonlinear fiber (HNLF). A continuous wave probe light is modulated by a polarization modulator (PolM) that is driven by a microwave signal to be phase shifted. The optical carrier and the first-order sidebands of the probe light experience different phase shifts due to the NPR induced by the control light in the HNLF. An optical bandpass filter is used to realize single-sideband modulation of the probe light by removing one of the first-order sidebands, as well as to reject the control light. After detecting by a photodetector, the phase of the recovered microwave signal is continuously tunable by adjusting the power of the control light. The proposed approach is theoretically analyzed and experimentally verified. A full 360° tunable phase shift is realized over an ultra-wideband frequency range from 8 to 38 GHz when the power of the control light is tuned from 0 to 570 mW.

All-optical generation of binary phase-coded microwave signal based on cross-polarization modulation in a highly nonlinear fiber.

We report a novel all-optical approach to generate a binary phase-coded microwave signal based on a cross-polarization modulation effect in a highly nonlinear fiber. The carrier frequency of the binary phase-coded microwave signal is widely tunable. Moreover, the precise π phase shift of the microwave signal is independent of the optical power of the control beam. The proposed approach is theoretically analyzed and experimentally verified. For a proof-of-concept demonstration, the binary phase-coded microwave signals with a carrier frequency of 20 GHz at a coding rate of 5 Gb/s and with a carrier frequency of 30 GHz at a coding rate of 7.5 Gb/s are experimentally generated. The pulse compression capability of the system is also evaluated. The measured and simulated results fit well with each other.

All-optical frequency upconversion for radio-over-fiber applications based on cross-gain modulation and cross-polarization modulation in a semiconductor optical amplifier.

We propose a novel all-optical frequency upconversion technique for radio-over-fiber (RoF) systems based on cross-gain modulation (XGM) and cross-polarization modulation (XPolM) in a semiconductor optical amplifier (SOA). A local oscillator signal is carried onto a continuous wave probe beam with orthogonally polarized single-sideband (SSB) modulation using a polarization modulator and a tunable optical filter. The intermediate frequency signal carried by a pump beam is only intensity modulated onto the sideband of the probe beam while the carrier of the probe beam is unmodulated thanks to the joint use of the XGM and XPolM effects in the SOA. This SSB upconversion scheme is inherently free from the chromatic-dispersion-induced power fading after transmission over single-mode fiber. The proposed scheme is theoretically analyzed and experimentally verified.

Photonic generation of triangular pulses based on nonlinear polarization rotation in a highly nonlinear fiber.

We propose a novel method to generate triangular pulses based on the nonlinear polarization rotation (NPR) effect in a highly nonlinear fiber. A continuous wave probe beam is polarization-rotated by an intensity-modulated control beam via the NPR effect. A polarization-division-multiplexing emulator is exploited to split the probe beam into two orthogonally polarized states with imbalanced time delay. After detection by a photodetector, a 90° microwave phase shifter is used to compensate the phases of the fundamental and the third-order harmonic components in order to generate triangular pulses. Triangular pulses at 5 and 6 GHz with full duty cycles are experimentally generated. The root mean square errors between the generated and the simulated waveforms are 3.6e-4 and 1e-4 for triangular pulses at 5 and 6 GHz, respectively.

Stable radio-frequency phase distribution over optical fiber by phase-drift auto-cancellation.

We report a new radio-frequency (RF) phase stabilization approach for long-haul optical fiber distribution. The phase drift of an RF signal induced by fiber-length variations can be canceled out automatically via RF mixing without using active phase discrimination and dynamic phase tracking. A key significance of our approach is that no assistant local oscillator (LO) signal is needed. Consequently, frequency estimation of the received RF signal, as well as frequency locking between the LO and the received RF signal, is no longer required, which simplifies the system. A proof-of-concept experiment shows that the phase drift of the received RF signal at 9.6 GHz is significantly reduced using the proposed method. The root mean square (RMS) timing jitter is 0.76 ps when a tunable optical delay line (TODL) inserted between the remote antenna unit (RAU) and local station is changed from 0 to 300 ps.

Photonic generation of background-free millimeter-wave ultra-wideband pulses based on a single dual-drive Mach-Zehnder modulator.

We propose a novel photonic approach for generating a background-free millimeter-wave (MMW) ultra-wideband (UWB) signal based on a conventional dual-drive Mach-Zehnder modulator (DMZM). One arm of the DMZM is driven by a local oscillator (LO) signal. The LO power is optimized to realize optical carrier suppressed modulation. The other arm is fed by a rectangular signal. The MMW UWB pulses are generated by truncating the continuous wave LO signal into a pulsed one in a photodetector (PD). The generated MMW UWB signal is background-free by eliminating the baseband frequency components because the optical power launched to the PD keeps constant all the time. The proposed method is theoretically analyzed and experimentally verified. The generated MMW UWB signal centered at a frequency of 26 GHz meets the Federal Communications Commission spectral mask very well.

miR-17-5p inhibitor enhances chemosensitivity to gemcitabine via upregulating Bim expression in pancreatic cancer cells.

BACKGROUND: miR-17-5p is reported to be overexpressed in pancreatic cancer, and it plays an important role in carcinogenesis and cancer progression. Gemcitabine is the standard first-line chemotherapeutic agent for pancreatic cancer, however the chemoresistance limits the curative effect. AIMS: In the present study, we investigated whether inhibition of miR-17-5p could enhance chemosensitivity to gemcitabine in pancreatic cancer cells. METHODS: miR-17-5p inhibitor was transfected to pancreatic cancer cell lines Panc-1 and BxPC3, and then cell proliferation, cell apoptosis, caspase-3 activation, and chemosensitivity to gemcitabine were measured in vitro. RESULTS: Our data showed that Panc-1 and BxPC3 cells transfected with miR-17-5p inhibitor showed growth inhibition, spontaneous apoptosis, higher caspase-3 activation, and increased chemosensitivity to gemcitabine. In addition, miR-17-5p inhibitor upregulated Bim protein expression in a dose-dependent manner without changing the Bim mRNA level, and it increased the activity of a luciferase reporter construct containing the Bim-3' untranslated region. CONCLUSIONS: These results prove that miR-17-5p negatively regulates Bim at the posttranscriptional level. We suggest that miR-17-5p inhibitor gene therapy would be a novel approach to chemosensitization for human pancreatic cancer.

Maslinic Acid Suppresses High Glucose-induced Inflammation by Epigenetically Inhibiting TXNIP Expression.

OBJECTIVE: Hyperglycemia-induced inflammation and subsequent endothelial injuries ultimately lead to the pathogenesis of cardiovascular diseases associated with high mortality, such as atherosclerosis. Maslinic acid (MA) is a phytochemical with anti-inflammatory activity. However, it remains unknown whether it can inhibit diabetes-associated cardiovascular inflammation. The present study aimed to determine the effect of MA on high glucose-induced endothelial inflammation and apoptosis in human umbilical vein endothelial cells (HUVECs) and to explore the underlying mechanism. METHODS: HUVECs were treated with high glucose to induce inflammation and apoptosis. Apoptosis was determined by flow cytometry. CCK-8 assay was used to examine cell viability. Production levels of cytokines were detected by quantitative realtime PCR (qPCR) and ELISA. Protein expression levels and signaling pathways activation were detected by Western blotting. RNA immunoprecipitation and qPCR were used to determine the N6-methyladenosine (m6A) levels of target mRNAs. RESULTS: MA promoted the recruitment of RNA demethylase ALKBH5 to TXNIP mRNA, and subsequently enhanced its m6A demethylation. By this means, MA decreased the stability of TXNIP mRNA and downregulated its expression level. Subsequently, reactive oxygen species (ROS) and production of pro-inflammatory cytokines, including TNF-α, IL-6 and IL-1ß, were inhibited. And high glucose-induced apoptosis in HUVECs was inhibited by MA. CONCLUSION: MA ameliorates high glucose-induced endothelial inflammation and injury, serving as a new potential therapeutic application for protecting against diabetes-associated atherosclerosis and other inflammatory diseases.

Copper-Catalyzed Aminoarylation of Alkenes via Aminyl Radical Addition and Aryl Migration.

We describe a new strategy for aminoarylation of alkenes by copper-catalyzed smiles rearrangement using O-benzoylhydroxylamines as the amine reagent. This method affords various ß-amino amide derivatives possessing a quaternary carbon center with wide functional group tolerance and high regioselectivity. The mechanistic studies indicate that the transformation can involve aminyl radical intermediates under acid-free condition.

Serum level of TSGF, CA242 and CA19-9 in pancreatic cancer.

AIM: To establish a method to detect the expression of the tumor specific growth factor TSGF, CA242 and CA19-9 in serum and evaluate their value in diagnosis of pancreatic cancer. METHODS: ELISA and Biochemical colorimetric assay were used to detect the serum content of TSGF, CA242 and CA19-9 in 200 normal cases, 52 pancreatitis patients and 96 pancreatic cancer patients. RESULTS: The positive likelihood ratios of TSGF, CA242 and CA19-9 were 5.4, 12.6 and 6.3, respectively, and their negative likelihood ratios were 0.10, 0.19 and 0.17, respectively. With single tumor marker diagnosed pancreatic cancer, the highest sensitivity and specificity of TSGF were 91.6% and 93.5%. In combined test with 3 markers, when all of them were positive, the sensitivity changed to 77.0% and the specificity and the positive predictive value were 100%. The levels of TSGF and CA242 were significantly higher in the patients with pancreatic cancer of head than those in the patients with pancreatic cancer of body, tail and whole pancreas, but the expression of CA19-9 had no correlation with the positions of the pancreatic cancer. The sensitivity of TSGF, CA242 and CA19-9 was increased with the progress in stages of pancreatic cancer. In stage I, the sensitivity of TSGF was markedly higher than CA242 and CA19-9. CONCLUSION: The combined use of TSGF, CA242 and CA19-9 expressions can elevate the specificity for pancreatic cancer diagnosis. And it shows that it plays an important role to differentiate positions and tissue typing. It is a forepart diagnosis for the pancreatic cancer by combination checking. There is very important correlation between the three markers and the pancreatic cancer.

[Characteristic and evaluation of soil pollution by heavy metal in different functional zones of Hohhot].

The residential areas, cultural and educational areas, city parks, commercial areas, urban roads, industrial zones, and development zones in Hohhot were selected as the research objects. Sixty-two soil samples were collected by triple subsampling technique in the seven functional zones. The aim of this study is to control the soil heavy metal pollution of Hohhot and provide the basic information. To investigate and analyze the heavy metal pollution in soil in different functional zones of Hohhot, the pollution of heavy metal was assessed with single factor pollution index and Nemerow integrated pollution index, and the pollution sources were discriminated by Principal Component Analysis. Contents of seven kinds of heavy metals were analyzed in different functional zones of Hohhot. The mean contents of heavy metals in soil samples exceeded the corresponding background values in the Inner Mongolia Autonomous Region. The mean contents of Cu and Zn were 2. 33 and 1. 85 times, respectively, as high as the soil background values of the Inner Mongolia Autonomous Region. Single factor pollution index showed that the urban soil in Hohhot has been polluted by heavy metals. The Cu pollution was the most severe in commercial areas, and the pollution degree was in the following order: Cu > Zn > Cr > Mn > As > Ni > Pb. Nemerow integrated pollution index showed that soils from the commercial areas were seriously contaminated by heavy metals. The soil of urban roads was moderately polluted. The soils from cultural and educational areas and the city parks were slightly polluted. The Nemerow integrated pollution index of the seven areas ranked as follows: commercial areas (3.03) > urban roads (2.12) > residential areas (1.98) > cultural and educational areas (1.81) > industrial zones (1.72) > development zones (1.36) > city parks (1. 28). The results of Principal Component Analysis showed that the heavy metals in soil of Hohhot came from different sources. Cr, Cu, Mn, Pb and Zn were mainly originated from anthropogenic sources while Ni and As were mainly controlled by natural sources. The healthy development of urban ecosystem has been threatened by soil heavy metal pollution in Hohhot.

Relationship between dietary macronutrient intake and the risk of age-related cataract in middle-aged and elderly patients in northeast China.

AIM: To examine the association between dietary macronutrient intake and the risk of age-related cataract (ARC) in middle-aged and elderly men. METHODS: A hospital-based case-control study was conducted from December 2009 to November 2011. Cases (n=360) were patients with cataract aged 45-85 years old, and controls (n=360) were patients who had been admitted to the same hospital for diseases not related with cataract. All subjects were interviewed using a structured interviewer-administrated questionnaire that included information on socio-demographic characteristics, lifestyle habits and detailed medical history, simultaneously, the dietary intakes of nutrients were collected via a valid semi-quantitative food frequency questionnaire (FFQ). The odds ratios (OR) and corresponding 95% confidence intervals (CI) of three types of ARC were estimated using multiple logistic regression models. RESULTS: After adjusting for multiple potential confounders, total dietary intake of carbohydrate was positively associated with cortical cataract, compared to controls in the lowest quartile, and the OR for cases in the highest quartile of intake was 2.471 (95%CI: 1.348-6.043, P=0.027). Higher dietary intakes of protein were protective for posterior subcapsular cataract (PSC) (OR=0.528, 95%CI: 0.148-0.869, P=0.023). Dietary fat intake was not associated with any type of cataract, however, participants in the highest quartile of polyunsaturated fatty acids intake had 2.7 times the risk of nuclear cataract as did those in the lowest quartile (OR=2.742, 95%CI: 1.790-4.200, P=0.033). CONCLUSION: A high intake of carbohydrate and polyunsaturated fatty acid may increase the odds of cortical and nuclear cataract, respectively, whereas high intake of protein, especially animal protein, may protect against PSC cataract. It is possible that dietary changes of target population may reduce the risk of ARC.