Effectiveness of fecal DNA syndecan-2 methylation testing for detection of colorectal cancer in a high-risk Chinese population.

BACKGROUND: Colorectal cancer (CRC) is among the most prevalent and life-threatening malignancies worldwide. Syndecan-2 methylation (mSDC2) testing has emerged as a widely used biomarker for early detection of CRC in stool and serum samples. Cancer (CRC) is among the most prevalent and life-threatening malignancies worldwide. mSDC2 testing has emerged as a widely used biomarker for early detection of CRC in stool and serum samples. AIM: To validate the effectiveness of fecal DNA mSDC2 testing in the detection of CRC among a high-risk Chinese population to provide evidence-based data for the development of diagnostic and/or screening guidelines for CRC in China. METHODS: A high-risk Chinese cohort consisting of 1130 individuals aged 40-79 years was selected for evaluation via fecal mSDC2 testing. Sensitivity and specificity for CRC, advanced adenoma (AA) and advanced colorectal neoplasia (ACN) were determined. High-risk factors for the incidence of colorectal lesions were determined and a logistic regression model was constructed to reflect the efficacy of the test. RESULTS: A total of 1035 high-risk individuals were included in this study according to established criteria. Among them, 16 suffered from CRC (1.55%), 65 from AA (6.28%) and 189 from non-AAs (18.26%); 150 patients were diagnosed with polyps (14.49%). Diagnoses were established based upon colonoscopic and pathological examinations. Sensitivities of the mSDC2 test for CRC and AA were 87.50% and 40.00%, respectively; specificities were 95.61% for other groups. Positive predictive values of the mSDC2 test for CRC, AA and ACN were 16.09%, 29.89% and 45.98%, respectively; the negative predictive value for CRC was 99.79%. After adjusting for other high-risk covariates, mSDC2 test positivity was found to be a significant risk factor for the occurrence of ACN (P < 0.001). CONCLUSION: Our findings confirmed that offering fecal mSDC2 testing and colonoscopy in combination for CRC screening is effective for earlier detection of malignant colorectal lesions in a high-risk Chinese population.

Septin 9 methylation analysis of lymph node micrometastases for predicting relapse of colorectal cancer.

BACKGROUND: Molecular markers for the detection of lymph node micrometastases of malignant tumors have been extensively investigated. However, epigenetic signatures have rarely been reported for identification of metastatic lymph nodes and disease relapse. Septin 9 is the most frequently reported hypermethylated gene in colorectal cancer (CRC). This study aimed to assess the clinical relevance of Septin 9 methylation in regional lymph nodes in recurrence/metastases of CRC. METHODS: We analyzed Septin 9 methylation of DNA from resected lymph nodes in 75 CRC patients with or without tumor recurrence using quantitative methylation-sensitive PCR (qMS-PCR). RESULTS: Of the 30 histologically negative lymph node CRC patients without recurrence (group 1), methylated Septin 9 was detected in 3 (10 %) cases. The positivity rate of methylated Septin 9 in group 2 containing 30 histologically node-negative CRC patients with recurrence was 30 % (9/30). For group 3, lymphatic invasion as well as tumor recurrence, 11 (73 %) out of 15 subjects had Septin 9 methylation-positive lymph nodes. Moreover, patients in group 3 had a higher level of methylated Septin 9 compared to subjects in group 1 and group 2 (p < 0.05). In addition, CRC patients with Septin 9 methylation in lymph nodes had significantly reduced survival (Log-rank P < 0.0001). CONCLUSION: Our data support the predictive role of Septin 9 methylation analysis of lymph node micrometastases for tumor relapse after surgery.

Lamella-nanostructured eutectic zinc-aluminum alloys as reversible and dendrite-free anodes for aqueous rechargeable batteries.

Metallic zinc is an attractive anode material for aqueous rechargeable batteries because of its high theoretical capacity and low cost. However, state-of-the-art zinc anodes suffer from low coulombic efficiency and severe dendrite growth during stripping/plating processes, hampering their practical applications. Here we show that eutectic-composition alloying of zinc and aluminum as an effective strategy substantially tackles these irreversibility issues by making use of their lamellar structure, composed of alternating zinc and aluminum nanolamellas. The lamellar nanostructure not only promotes zinc stripping from precursor eutectic Zn88Al12 (at%) alloys, but produces core/shell aluminum/aluminum sesquioxide interlamellar nanopatterns in situ to in turn guide subsequent growth of zinc, enabling dendrite-free zinc stripping/plating for more than 2000 h in oxygen-absent aqueous electrolyte. These outstanding electrochemical properties enlist zinc-ion batteries constructed with Zn88Al12 alloy anode and KxMnO2 cathode to deliver high-density energy at high levels of electrical power and retain 100% capacity after 200 hours.

Dual-phase nanostructuring of layered metal oxides for high-performance aqueous rechargeable potassium ion microbatteries.

Aqueous rechargeable microbatteries are promising on-chip micropower sources for a wide variety of miniaturized electronics. However, their development is plagued by state-of-the-art electrode materials due to low capacity and poor rate capability. Here we show that layered potassium vanadium oxides, KxV2O5·nH2O, have an amorphous/crystalline dual-phase nanostructure to show genuine potential as high-performance anode materials of aqueous rechargeable potassium-ion microbatteries. The dual-phase nanostructured KxV2O5·nH2O keeps large interlayer spacing while removing secondary-bound interlayer water to create sufficient channels and accommodation sites for hydrated potassium cations. This unique nanostructure facilitates accessibility/transport of guest hydrated potassium cations to significantly improve practical capacity and rate performance of the constituent KxV2O5·nH2O. The potassium-ion microbatteries with KxV2O5·nH2O anode and KxMnO2·nH2O cathode constructed on interdigital-patterned nanoporous metal current microcollectors exhibit ultrahigh energy density of 103 mWh cm-3 at electrical power comparable to carbon-based microsupercapacitors.

Lipid-Wrapped Upconversion Nanoconstruct/Photosensitizer Complex for Near-Infrared Light-Mediated Photodynamic Therapy.

Photodynamic therapy (PDT) is a noninvasive medical technology that has been applied in cancer treatment where it is accessible by direct or endoscope-assisted light irradiation. To lower phototoxicity and increase tissue penetration depth of light, great effort has been focused on developing new sensitizers that can utilize red or near-infrared (NIR) light for the past decades. Lanthanide-doped upconversion nanoparticles (UCNPs) have a unique property to transduce NIR excitation light to UV-vis emission efficiently. This property allows some low-cost, low-toxicity, commercially available visible light sensitizers, which originally are not suitable for deep tissue PDT, to be activated by NIR light and have been reported extensively in the past few years. However, some issues still remain in the UCNP-assisted PDT platform such as colloidal stability, photosensitizer loading efficiency, and accessibility for targeting ligand installation, despite some advances in this direction. In this study, we designed a facile phospholipid-coated UCNP method to generate a highly colloidally stable nanoplatform that can effectively load a series of visible light sensitizers in the lipid layers. The loading stability and singlet oxygen generation efficiency of this sensitizer-loaded lipid-coated UCNP platform were investigated. We also have demonstrated the enhanced cellular uptake efficiency and tumor cell selectivity of this lipid-coated UCNP platform by changing the lipid dopant. On the basis of the evidence of our results, the lipid-complexed UCNP nanoparticles could serve as an effective photosensitizer carrier for NIR light-mediated PDT.

[Multi-Element Detection in Molten Steel with Laser-Induced Breakdown Spectroscopy].

On-line element content detection in iron and steel industry is one of the key techniques to ensure the quality in iron and steel metallurgy. Laser Induced Breakdown Spectroscopy (LIBS) has been applied to on-line components detection in molten steel. We have built LIBS system for components detection of molten steel in laboratory. The system consists of a Q-switched Nd∶YAG laser (repetition rate 10 Hz, wavelength 1 064 nm, pulse length 10 ns, pulse energy about 120 mJ), high frequency induction furnace (temperature 1 600 ℃), spectrometer (wavelength range 186～310 nm, spectral resolution 0.1 nm), laser focusing and spectral signal collecting system. Multi-elements were detected in molten steel with the application of deep-UV detector coating and solarization resistant fibers. According to the calibration curves of C, S, Mn and Cr, the limit of detections are 169, 15, 58.9 and 210 µg·g-1 respectively. The R-squares of calibration curves of C, S, Mn, and Cr are better than 0.96 by using appropriate analytical lines and reference lines. At the same time, through the comparison of different elements, we find the best calibration curve of different element need different delay conditions.

[The auto-focusing remote laser-induced breakdown spectroscopy system].

The present paper presents an auto-focus laser-induced breakdown spectroscopy (LIBS) remote measuring system. This system contains a Schwarzschild telescope, which consists of a convex mirror and a concave mirror. The two spherical mirrors are coaxially placed. The convex mirror is mounted on a motorized linear translation stage. With this motorized linear translation stage, the convex mirror can move along the optical axis to change the spacing between the convex mirror and the concave mirror. Therefore the focal length can be adjusted to focus the laser on samples at different distances and collect the plasma spectra. The advantages of the telescope system include, firstly, the light path of laser focusing and spectra signal collection is the same, which make it easier for mounting and collimation; secondly, the light path of the telescope uses total reflection type, which is fit for the detection in ultra-violate region; finally, the telescope consists of only two spherical mirrors which are relatively easier to manufacture. Within the translation range of the motorized linear translation stage, the focal length of the telescope in this paper can be adjusted from 1.5 to 3.6 m. The diameter of the focusing spot varies from 0.5 to 1.0 mm. Utilizing this telescope system, LIBS experiments were conducted using copper sample. And the characteristic lines of Cu element (Cu I 223.01 nm, Cu I 224.43 nm) obtained are used for the auto focusing. By investigating the relation of the area of spectral lines covered and the spacing between the mirrors, the optimal laser focusing location was obtained. The LIBS experiment results show that the system functions well, fulfilling the demand of remote ablation of sample and LIBS spectral measuring, and the telescope is able to auto-focus the laser on samples at different position to perform remote LIBS experiment.

The effects of fluorine-contained molecules on improving the polymer solar cell by curing the anomalous S-shaped I-V curve.

In this study, we investigate the effects of fluorinated poly(3,4-ethylene dioxythiophene):poly(styrenesulfonate) buffer layer on the performance of polymer photovoltaic cells. We demonstrate for the first time, the deterioration of the device performance can be effectively mended by modifying the interface between the active layer and buffer layer with heptadecafluoro-1,1,2,2-tetra-hydro-decyl trimethoxysilane (PFDS) and perfluorononane. Device performance shows a substantial enhancement of short-circuit current from 7.90 to 9.39 mA/cm(2) and fill factor from 27% to 53%. The overall device efficiency was improved from 0.98% to 3.12% for PFDS modified device. The mechanism of S-shape curing is also discussed. In addition, the stability of modified devices shows significant improvement than those without modification. The efficiency of the modified devices retains about half (1.88%) of its initial efficiency (4.1%) after 30 d compared to the unmodified ones (0.61%), under air atmosphere.

[A method for time-resolved laser-induced breakdown spectroscopy measurement].

Laser-Induced Breakdown Spectroscopy (LIBS) is strongly time related. Time-resolved LIBS measurement is an important technique for the research on laser induced plasma evolution and self-absorption of the emission lines. Concerning the temporal characteristics of LIBS spectrum, a method is proposed in the present paper which can achieve micros-scale time-resolved LIBS measurement by using general ms-scale detector. By setting different integration delay time of the ms-scale spectrum detector, a series of spectrum are recorded. And the integration delay time interval should be longer than the worst temporal precision. After baseline correction and spectrum fitting, the intensity of the character line was obtained. Calculating this intensity with differential method at a certain time interval and then the difference value is the time-resolved line intensity. Setting the plasma duration time as X-axis and the time-resolved line intensity as Y-axis, the evolution curve of the character line intensity can be plotted. Character line with overlap-free and smooth background should be a priority to be chosen for analysis. Using spectrometer with ms-scale integration time and a control system with temporal accuracy is 0.021 micros, experiments carried out. The results validate that this method can be used to characterize the evolution of LIBS characteristic lines and can reduce the cost of the time-resolved LIBS measurement system. This method makes high time-resolved LIBS spectrum measurement possible with cheaper system.

Direct assessment of the mechanical modulus of graphene co-doped with low concentrations of boron-nitrogen by a non-contact approach.

Boron and nitrogen co-doping has been shown to be an effective way to induce a band gap in graphene for electrical applications but only a few theoretical studies have been done to understand the elastic and mechanical properties of the modified graphene. Until now, no experimental assessment of the mechanical modulus of boron-nitrogen-doped graphene (BNG) has been reported in the literature. Here, we demonstrate a novel non-contact approach to determine the in-plane stiffness of BNG at low BN concentrations. The in-plane stiffness of BNG with 2 at% BN concentration was estimated to be about 309 N m(-1), which is lower than that of pristine graphene, in good agreement with some theoretical studies. Moreover, we correlated the conductivity of BNG with induced strain and found the BNG to be more sensitive than pristine graphene in response to externally applied strain. This result indicates that BNG is a more suitable material than graphene for strain sensor applications.

Surface plasmon resonance-induced color-selective Au-peapodded silica nanowire photodetectors with high photoconductive gain.

We report the optoelectronic device properties of individual Au-silica hybrid nanowires prepared by microwave plasma enhanced chemical vapor deposition. Due to the surface plasmon resonance (SPR) effect the photo-responsivity peak strongly depends on the shape of the embedded gold nanostructures in the silica nanowire in which the shape can be modified by controlling the growth time of Au-silica nanowires. Finite difference time domain (FDTD) simulation shows that the electric field distribution profiles of Au-silica hybrid nanowires support the photo-responsivity spectrum results. The photodetector performance of the Au-NPs@silica nanowire is investigated. The single Au-NPs@silica nanowire exhibits unique photo-responsivity in the visible range (500 nm), high selectivity, high photoconductive gain, and very fast rise (141 µs) and decay (298 µs) time constants. Furthermore, the mechanism for the high photoconductive gain is also discussed. This result implies that the Au-NPs@silica nanowire can be applied for future nanoscale optoelectronic devices.

High k nanophase zinc oxide on biomimetic silicon nanotip array as supercapacitors.

A 3D trenched-structure metal-insulator-metal (MIM) nanocapacitor array with an ultrahigh equivalent planar capacitance (EPC) of ~300 µF cm(-2) is demonstrated. Zinc oxide (ZnO) and aluminum oxide (Al2O3) bilayer dielectric is deposited on 1 µm high biomimetic silicon nanotip (SiNT) substrate using the atomic layer deposition method. The large EPC is achieved by utilizing the large surface area of the densely packed SiNT (!5 × 10(10) cm(-2)) coated conformally with an ultrahigh dielectric constant of ZnO. The EPC value is 30 times higher than those previously reported in metal-insulator-metal or metal-insulator-semiconductor nanocapacitors using similar porosity dimensions of the support materials.

Band gap engineering of chemical vapor deposited graphene by in situ BN doping.

Band gap opening and engineering is one of the high priority goals in the development of graphene electronics. Here, we report on the opening and scaling of band gap in BN doped graphene (BNG) films grown by low-pressure chemical vapor deposition method. High resolution transmission electron microscopy is employed to resolve the graphene and h-BN domain formation in great detail. X-ray photoelectron, micro-Raman, and UV-vis spectroscopy studies revealed a distinct structural and phase evolution in BNG films at low BN concentration. Synchrotron radiation based XAS-XES measurements concluded a gap opening in BNG films, which is also confirmed by field effect transistor measurements. For the first time, a significant band gap as high as 600 meV is observed for low BN concentrations and is attributed to the opening of the π-π* band gap of graphene due to isoelectronic BN doping. As-grown films exhibit structural evolution from homogeneously dispersed small BN clusters to large sized BN domains with embedded diminutive graphene domains. The evolution is described in terms of competitive growth among h-BN and graphene domains with increasing BN concentration. The present results pave way for the development of band gap engineered BN doped graphene-based devices.

Growth of ß-Ga2O3 and GaN nanowires on GaN for photoelectrochemical hydrogen generation.

Enhanced photoelectrochemical (PEC) performances of Ga(2)O(3) and GaN nanowires (NWs) grown in situ from GaN were demonstrated. The PEC conversion efficiencies of Ga(2)O(3) and GaN NWs have been shown to be 0.906% and 1.09% respectively, in contrast to their 0.581% GaN thin film counterpart under similar experimental conditions. A low crystallinity buffer layer between the grown NWs and the substrate was found to be detrimental to the PEC performance, but the layer can be avoided at suitable growth conditions. A band bending at the surface of the GaN NWs generates an electric field that drives the photogenerated electrons and holes away from each other, preventing recombination, and was found to be responsible for the enhanced PEC performance. The enhanced PEC efficiency of the Ga(2)O(3) NWs is aided by the optical absorption through a defect band centered 3.3 eV above the valence band of Ga(2)O(3). These findings are believed to have opened up possibilities for enabling visible absorption, either by tailoring ion doping into wide bandgap Ga(2)O(3) NWs, or by incorporation of indium to form InGaN NWs.

[Laser-induced breakdown spectroscopy system for elements analysis in high-temperature and vacuum environment].

Laser-induced breakdown spectroscopy (LIBS) is one of the most promising technologies to be applied to metallurgical composition online monitoring in these days. In order to study the spectral characters of LIBS spectrum and to investigate the quantitative analysis method of material composition under vacuum and high temperature environment, a LIBS measurement system was designed and set up which can be used for conducting experiments with high-temperature or molten samples in different vacuum environment. The system consists of a Q-switched Nd : YAG laser used as the light source, lens with different focus lengths used for laser focusing and spectrum signal collecting, a spectrometer used for detecting the signal of LIBS spectrums, and a vacuum system for holding and heating the samples while supplying a vacuum environment. The vacuum was achieved and maintained by a vacuum pump and an electric induction furnace was used for heating the system. The induction coil was integrated to the vacuum system by attaching to a ceramic sealing flange. The system was installed and testified, and the results indicate that the vacuum of the system can reach 1X 10(-4) Pa without heating, while the heating temperature could be about 1 600 degreeC, the system can be used for melting metal samples such as steel and aluminum and get the LIBS spectrum of the samples at the same time. Utilizing this system, LIBS experiments were conducted using standard steel samples under different vacuum or high-temperature conditions. Results of comparison between LIBS spectrums of solid steel samples under different vacuum were achieved, and so are the spectrums of molten and solid steel samples under vacuum environment. Through data processing and theoretical analyzing of these spectrums, the initial results of those experiments are in good agreement with the results that are presently reported, which indicates that the whole system functions well and is available for molten metal LIBS experiment under vacuum environment.

Gold nanoparticle-modulated conductivity in gold peapodded silica nanowires.

We report the enhanced electrical conductivity properties of single gold-peapodded amorphous silica nanowires synthesized using microwave plasma enhanced chemical vapor deposition. Dark conductivity of the gold-peapodded silica nanowires can be adjusted by controlling the number of incorporated metal nanoparticles. The temperature-dependent conductivity measurement reveals that the band tail hopping mechanism dominates the electron transport in the gold-peapodded silica nanowires. The high conductivity in the nano-peapodded nanowires with more embedded gold-nanoparticles can be explained by the higher density of hopping states and shorter hopping distance. These Au-embedded amorphous silica nanowires have provided a new approach to enhance not only the electron conduction, but also the chemical-sensor response/sensitivity.