Xiao-Wei Sun

Nanyang Technological University, Singapore, Singapore

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Publications (52)136.27 Total impact

  • Article: Time-varying pattern of recurrence risk for gastric cancer patients.
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    ABSTRACT: This study analyzed the time-varying pattern of the recurrence risk for gastric cancer after surgery. A total of 1,222 gastric patients undergoing D2 resection surgery were studied retrospectively. The annual recurrence hazard curve for all of the populations showed one early peak and a late rise within 10 years after the surgery. The first major recurrence peak covers the first 3 years after the surgery, rising to a maximum at 1.5 years after surgery, followed by a decline until 7.5 years after the surgery, at which point the curve began to rise again. A subgroup analysis of this pattern also revealed that the curves of the patients with bigger tumors, poorly differentiated/undifferentiated adenocarcinomas, lymphatic/venous invasion, T3 and T4, node positive or with fewer lymph nodes retrieved were steeper. Chemotherapy can reduce the hazard rate for recurrence of gastric cancer. Our study confirms the time-varying pattern of the recurrence risk for gastric cancer, and it further supports the hypothesis of tumor dormancy after surgery. To effectively reduce the recurrence risk, new adjuvant therapies beyond chemotherapy may be needed.
    Medical Oncology 06/2013; 30(2):514. · 2.14 Impact Factor
  • Article: Facile Synthesis of Luminescent AgInS2 -ZnS Solid Solution Nanorods.
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    ABSTRACT: Highly luminescent semiconducting AgInS2 -ZnS solid solution nanorods are successfully prepared by a facile one-pot solvothermal method. The resulting solid solution nanorods with length of 32 ± 5 nm are formed by fast growth of the AgInS2 -rich solid solution head, followed by slow growth of the ZnS-rich solid solution tail. Photoluminescence studies on the solid solution nanorods reveal strong photoluminescence with peak emission wavelengths tunable from 650 to 700 nm.
    Small 04/2013; · 8.35 Impact Factor
  • Article: Food restriction alters villi morphology in obese rats: gut mechanism for weight regain?
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    ABSTRACT: Weight regain after a long-term weight-loss program is a greater problem in obesity treatment than is weight reduction. Hence, the gut may elevate the absorption rate and nutrient transportation remarkably during chronic food restriction. The extension of gut absorption may be one possible reason for weight regain. But there is little information about the mechanisms that regulate intestinal absorption during food restriction. In this study, we show that the surface absorptive areas of gut villi may be enlarged in the jejunum of rats maintained on a food restriction regimen compared with animals submitted to swimming or sedentary behavior. Our findings show that simply reducing the amount of food intake results in an increased appetite accompanied with obvious weight regain, and suggest that the resulting enlargement of villi surface areas plays a key role in the regain of weight reduction. These results bolster accumulating evidence that gut absorption may be a substantial mechanism for resistance of weight loss and enhancing the weight regain process.
    Experimental Biology and Medicine 09/2012; 237(9):993-9. · 2.64 Impact Factor
  • Article: A complementary electrochromic device with highly improved performance based on brick-like hydrated tungsten trioxide film.
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    ABSTRACT: Uniform and well adhesive nanostructured hydrated tungsten trioxide (3WO3 x H2O) films were grown on fluorine doped tin oxide (FTO) substrate via a facile and template-free crystal-seed-assisted hydrothermal method by addition of ammonium sulfate ((NH4)2SO4) and hydrogen peroxide (H2O2). X-ray diffraction (XRD) studies indicated that the films are of orthorhombic structure. Scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HRTEM) analysis showed that the film was composed of brick-like nanostructures with a preferred growing direction along (002). The influence of seed layer, (NH4)2SO4 and H2O2 on the products were also studied. The film showed good cyclic stability, comparable switching speed and coloration efficiency (30.1 cm2 C(-1)). A complementary electrochromic device based on the film and Prussian blue depicted highly improved color contrast, coloration/bleaching response (1.8 and 3.7 s respectively) and coloration efficiency (164.6 cm2 C(-1)).
    Journal of Nanoscience and Nanotechnology 05/2012; 12(5):3838-47. · 1.56 Impact Factor
  • Article: Full visible range covering InP/ZnS nanocrystals with high photometric performance and their application to white quantum dot light-emitting diodes.
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    ABSTRACT: High-quality InP/ZnS core-shell nanocrystals with luminescence tunable over the entire visible spectrum have been achieved by a facile one-pot solvothermal method. These nanocrystals exhibit high quantum yields (above 60%), wide emission spectrum tunability and excellent photostability. The FWHM can be as narrow as 38 nm, which is close to that of CdSe nanocrystals. Also, making use of these nanocrystals, we further demonstrated a cadmium-free white QD-LED with a high color rendering index of 91. The high-performance of the resulting InP/ZnS NCs coupled with their low intrinsic toxicity may further promote industrial applications of these NC emitters.
    Advanced Materials 04/2012; 24(30):4180-5. · 13.88 Impact Factor
  • Article: Hierarchical ZnO/Bi2O3 nanostructures: synthesis, characterization, and electron-beam modification
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    ABSTRACT: Two types of ZnO/Bi2O3 nanonecklace heterostructures were fabricated using the vapor-phase transport (VPT) method for the first time. These hierarchical structures were well characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM) with energy dispersive spectroscopy (EDS) attached. The growth mechanism of the novel structures were proposed based on these characterizations. Electron-beam irradiation was found to be a powerful and controllable tool in further tailoring such ZnO/Bi2O3 nanonecklace heterostructures. In addition, photoluminescence (PL) emission from the hierarchical nanostructures showed enhancement comparing to the pure Bi2O3 powder.
    Applied Physics A 04/2012; 98(1):91-96. · 1.63 Impact Factor
  • Article: Nitrogen-doped carbon nanotube-based bilayer thin film as transparent counter electrode for dye-sensitized solar cells (DSSCs).
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    ABSTRACT: Carbon nanotubes (CNTs) have been widely considered as one of the promising candidates for replacing fluorine-doped tin oxide (FTO)/platinum (Pt) electrodes to reduce the fabrication cost of dye-sensitized solar cells (DSSCs). Here, we report that a bilayer transparent film containing N-doped CNTs (which are highly catalytic) and normal CNTs (which are highly conductive) as a counter electrode in DSSCs results in efficiencies up to 2.18%, yet still maintains a good transparency with a transmittance of approximately 57% at 550 nm.
    Chemistry - An Asian Journal 03/2012; 7(3):541-5. · 4.50 Impact Factor
  • Article: Levels and congener profiles of polybrominated diphenyl ethers (PBDEs) in primipara breast milk from Shenzhen and exposure risk for breast-fed infants.
    Jian Gang Zhang, Xiao Wei Sun, Hua Ai
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    ABSTRACT: This study aimed at revealing the levels of polybrominated diphenyl ethers (PBDEs) in breast milk from primipara in Shenzhen (China), and estimating daily intake of PBDEs for breast-fed infants. Concentrations of 7 PBDEs were measured in 60 breast milk samples by isotope dilution HRGC/HRMS (high-resolution gas chromatography/high-resolution mass spectrometry). The intake of PBDEs for breast-fed infants was estimated based on the infant's daily milk consumption. The range of total concentration of 7 PBDEs congeners in samples was 2.6-188.6 ng g(-1) lipid (mean: 14.8 ng g(-1) lipid; median: 7.2 ng g(-1) lipid). The mean estimated daily intake of PBDEs by breast-fed infants ranged from 9.9 to 335.9 ng kg(-1) body weight (bw) per day (mean: 52.5 ng kg(-1) bw per day; median: 28.6 ng kg(-1) bw per day). The levels of PBDEs body burden in the recruited mothers of Shenzhen were higher than those reported previously for the general population from other areas in China. No significant correlations were found between the body burden of PBDEs and the mothers' age, pre-pregnancy BMI, dietary habits, duration of residence in Shenzhen, weight and length of the newborns. BDE-47 and BDE-153 were major PBDE congeners in milk samples, while the congeners of BDE-183 and BDE-28 were also high in Shenzhen. The situation may be attributed to the special economic pattern including electronic production in Shenzhen in the past three decades. Continuous surveillance on PBDEs levels in human milk is needed in order to accurately evaluate the environmental impact of PBDEs to human health in Shenzhen.
    Journal of Environmental Monitoring 03/2012; 14(3):893-900. · 1.99 Impact Factor
  • Article: The prognostic value of harvested lymph nodes and the metastatic lymph node ratio for gastric cancer patients: results of a study of 1,101 patients.
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    ABSTRACT: To investigate whether the recommendation to remove 15 lymph nodes that is used in the staging system is necessary to assess gastric cancer progression and to evaluate whether our metastatic lymph node ratio dividing method, adapted from the AJCC's (American Joint Committee on Cancer) 7(th) TNM staging system, is helpful for the patients with fewer than 15 harvested lymph nodes. We performed a retrospective study of 1101 patients with histologically diagnosed gastric cancer who underwent a D2 gastrectomy at the Sun Yat-sen University Cancer Center between January 2001 and December 2010. The Kappa and Chi-squared tests were employed to compare the clinicopathological variables. The Kaplan-Meier method and Cox regression were employed for the univariate and multivariate survival analyses. In the trial, 346, 601 and 154 patients had 0-14, 15-30 and more than 30 lymph nodes harvested, respectively. The median survival times of patients with different lymph nodes harvested in N0, N1, N2 and N3a groups were 45.43, 54.28 and 66.95 months (p = 0.068); 49.22, 44.25 and 56.72 months (p<0.001), 43.94, 47.97 and 35.19 months (p = 0.042); 32.88, 42.76 and 23.50 months (p = 0.016). Dividing the patients who had fewer than 15 lymph nodes harvested by the metastatic lymph node ratio at 0, 0.13 and 0.40, the median survival times of these 4 groups were 70.6, 50.5, 53.5 and 30.7 months (p<0.001). After re-categorising these 4 groups into the N0, N1, N2, N3a groups, the histological grade, T staging, premier N staging, and restaged N staging were the independent prognostic factors. Large numbers of lymph nodes harvested in radical gastrectomy do not cause stage migration. For those patients with a small number of harvested lymph nodes, their stage should be divided by the metastatic lymph node ratio, referred to in the TNM staging system, to assign them an accurate stage.
    PLoS ONE 01/2012; 7(11):e49424. · 4.09 Impact Factor
  • Article: Efficient synthesis of plate-like crystalline hydrated tungsten trioxide thin films with highly improved electrochromic performance.
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    ABSTRACT: Plate-like hydrated tungsten trioxide (3WO(3)·H(2)O) films were grown on a fluorine doped tin oxide (FTO) coated transparent conductive substrate via an efficient, facile and template-free hydrothermal method. The film exhibited a fast coloration/bleaching response (t(c90%) = 4.3 s and t(b90%) = 1.4 s) and a high coloration efficiency (112.7 cm(2) C(-1)), which were probably due to a large surface area.
    Chemical Communications 11/2011; 48(3):365-7. · 6.17 Impact Factor
  • Article: Transition from anodic titania nanotubes to nanowires: arising from nanotube growth to application in dye-sensitized solar cells.
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    ABSTRACT: Anodic formation of titania nanowires has been interpreted using a bamboo-splitting model; however, a number of phenomena are difficult to explain with this model. Herein, transition from nanotubes to nanowires is investigated by varying the anodizing conditions. The results indicate that the transition requires a large number of hydrogen ions to reduce the passivated area of tube walls, and therefore can be observed only in an intermediate chemical dissolution environment. Accordingly, a model in terms of stretching and splitting is proposed to interpret the transition process. The model provides a basis to suppress the nanowires with surface treatments before anodization and to clear the nanowires with an ultrasonication process after anodization. The nanotube-nanowire transition also arises when the tubes are directly used in dye-sensitized solar cells. Treatment with titanium tetrachloride solution for about 10 h is found to be effective in suppressing the nanowires, and thus improving the photovoltaic properties of the solar cells.
    ChemPhysChem 11/2011; 12(18):3634-41. · 3.41 Impact Factor
  • Article: Europium (II)-doped microporous zeolite derivatives with enhanced photoluminescence by isolating active luminescence centers.
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    ABSTRACT: Solid-state reaction is the most common method for preparing luminescent materials. However, the luminescent dopants in the hosts tend to aggregate in the high-temperature annealing process, which causes adverse effect in photoluminescence. Herein, we report a novel europium (II)-doped zeolite derivative prepared by a combined ion-exchange and solid-state reaction method, in which the europium (II) ions are isolated to a large extent by the micropores of the zeolite. Excited by a broad ultraviolet band from 250 to 420 nm, a strong blue emission peaking at 450 nm was observed for these Eu-embedded zeolites annealed at 800 °C in a reducing atmosphere. The zeolite host with pores of molecular dimension was found to be an excellent host to isolate and stabilize the Eu(2+) ions. The as-obtained europium (II)-doped zeolite derivative showed an approximately 9 fold enhancement in blue emission compared to that of the general europium (II)-doped aluminosilicates obtained by conventional solid-state reaction, indicating that, by isolating active luminescence centers, it is promising to achieve highly luminescent materials. Also, the strong blue emission with broad UV excitation band suggests a potential candidate of phosphor for ultraviolet excited light-emitting diode.
    ACS Applied Materials & Interfaces 11/2011; 3(11):4431-6. · 4.53 Impact Factor
  • Article: Tailoring insoluble nanobelts into soluble anti-UV nanopotpourris.
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    ABSTRACT: Soluble, transparent and anti-UV nanopotpourris have been prepared by tailoring long nanobelts. The strains and layered structures facilitate the breaking of the as-synthesized nanobelts under an applied mechanical action. The developed tailoring process of nanobelts is a general top-down secondary processing of layered nanostructures at the nanoscale level, which can be expended to the modifications of layered nanowires, nanotubes and hierarchical nanostructures. By tailoring, the size, morphology and solubility are modified, which may open up an area of advanced processing of nanomaterials and hint at some potential applications. Because of the excellent solubility of the tailored nanopotpourris, they are easily dispersed in cosmetics or polymer films, which are quite useful for some anti-UV protection applications, such as anti-UV sunscreen creams and anti-UV window films for vehicles and buildings.
    Nanoscale 11/2011; 3(11):4742-5. · 5.91 Impact Factor
  • Article: Warm-white light-emitting diodes integrated with colloidal quantum dots for high luminous efficacy and color rendering: reply to comment.
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    ABSTRACT: The correlated color temperatures and the corresponding color rendering indices calculated using actual experimental data (and not any prediction) in the original Letter [Opt. Lett. 35 , 3372 (2010)] are correct. In addition, here the color rendering of our white LEDs integrated with nanocrystal quantum dots (NQDs) is provided for all test samples. Also, a new NQD-LED design with both high luminous efficacy of optical radiation and CRI is presented to have a chromaticity point in the quadrangle stated in the comment Letter [Opt. Lett. 36 , 2851 (2011)]. The points made in the original Letter and all the calculation results provided therein are valid.
    Optics Letters 08/2011; 36(15):2852. · 3.40 Impact Factor
  • Article: UV and Visible Electroluminescence From a Heterojunction by Metal–Organic Chemical Vapor Deposition
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    ABSTRACT: A Sn-doped Ga<sub>2</sub>O<sub>3</sub> thin film was deposited on a n<sup>+</sup>-Si substrate by metal-organic chemical vapor deposition. The Ga<sub>2</sub>O<sub>3</sub> film was found to be amorphous-like and exhibited n-type conduction with Sn doping. Room-temperature electroluminescence was clearly observed from the Sn:Ga<sub>2</sub>O<sub>3</sub>/n<sup>+</sup> -Si diode, including an ultraviolet (UV) emission at ~ 370 nm, a yellow emission at ~ 580 nm, and a red emission at ~ 680 nm. The UV emission is assigned to the transition from Sn<sub>Ga</sub> donor to the V <sub>Ga</sub> acceptor, whereas the visible emissions were assigned to be related to the dangling bond defects.
    IEEE Transactions on Electron Devices 06/2011; · 2.32 Impact Factor
  • Article: No survival benefit from postoperative adjuvant chemotherapy after D2 radical resection for the patients with stage II gastric cancer.
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    ABSTRACT: To evaluate the effect of 2 regimens of postoperative combination chemotherapies on the prognosis of early stage gastric cancer patients. A total of 268 patients with stage II gastric cancer underwent D2 resection in our Cancer Center between January 1990 and December 2006 were recruited. Among them, 34 patients received the FAM regimen (5-fluorouracil [5-FU] 600 mg/m(2) intravenous [IV] drip on days 1, 8, 29, and 36; doxorubicin 30 mg/m(2) IV bolus injection on days 1 and 29; and mitomycin-C 10 mg/m(2) IV bolus injection on day 1; repeated every 8 weeks) and 81 patients received the FOLFOX regimen (oxaliplatin 100 mg/m(2) IV drip on days 1 and 15; leucovorin 400 mg/m(2) IV drip on days 1 and 15; 5-FU 400 mg/m(2) IV bolus injection; 5-FU 2.4/3.0 mg/m(2) continuous IV infusion for 48 hours on day 1, 2, 15, and 16; repeated every 4 weeks for at least 4 cycles). Patients were followed-up until December 2008. The Kaplan-Meier method was used to compare survival rates between treatment groups. The 1-, 3-, 5-, and 10-year survival rates for the patients who received postoperative chemotherapy versus the patients who underwent surgery only were 98%, 84%, 58%, 18% versus 96%, 78%, 59%, 22%, respectively (P > 0.05). Furthermore, the survival rates for patients who received the FAM and FOLFOX regimens were not significantly different (P > 0.05). Postoperative adjuvant chemotherapy did not produce survival benefits for the patients with stage II gastric cancer. Randomized controlled clinical trials are demanded to confirm the finding from this study.
    American journal of clinical oncology 06/2011; 34(3):309-13. · 2.21 Impact Factor
  • Source
    Article: Polarization-dependent circular Dammann grating made of azo-dye-doped liquid crystals.
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    ABSTRACT: A polarization-dependent circular Dammann grating (CDG) was generated from an azo-dye-doped liquid crystal (LC) cell. A simple multiexposure photo-alignment process was used to fabricate a binary phase LC CDG zone plane, which was composed of an odd zone with a twisted nematic LC structure and an even zone with a homogenous LC structure. A two-order CDG with equal-intensity rings was produced through a Fourier transform. The maximum zeroth and first diffraction orders of obtained CDG can be separately achieved by rotating the analyzer's polarization direction. The CDG using an azo-dye-doped LC cell can be used to generate diffractions by lasers in a broad wavelength range, hence expanding possible device applications.
    Applied Optics 05/2011; 50(15):2316-21. · 1.41 Impact Factor
  • Article: Broadband absorption enhancement in randomly positioned silicon nanowire arrays for solar cell applications.
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    ABSTRACT: In this Letter, the optical properties of randomly positioned silicon nanowire arrays are studied. The result shows that position randomization with a filling ratio larger than 36% renders better absorptance over a broadband ranging from 300 to 1130 nm compared to regular structures. The ultimate efficiency of a 48% filling ratio position randomized nanowire structure is 13.4% higher compared to the optimized regularly arranged nanowire structure with the same thickness. The absorptance enhancement of random structures is attributed to lowered reflectance, more supported resonant modes, and broadening of existing resonance.
    Optics Letters 05/2011; 36(10):1884-6. · 3.40 Impact Factor
  • Article: Enhanced optical absorption in nanopatterned silicon thin films with a nano-cone-hole structure for photovoltaic applications.
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    ABSTRACT: In this paper, the optical properties of the silicon nano-cone-hole (NCH) structure array are studied. The ultimate efficiency of the optimized NCH array is enhanced by 23.11% compared to an optimized nanohole array of the same thickness. The absorptance enhancement of the NCH arrays is attributed to its lowered reflectance, more supported resonant modes, and enhanced mode interaction. The angular dependence of ultimate efficiency is also investigated.
    Optics Letters 05/2011; 36(9):1713-5. · 3.40 Impact Factor
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    Article: Influence of Channel Layer Thickness on the Electrical Performances of Inkjet-Printed In-Ga-Zn Oxide Thin-Film Transistors
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    ABSTRACT: Inkjet-printed In-Ga-Zn oxide (IGZO) thin-film transistors (TFTs) with bottom-gate bottom-contact device architecture are studied in this paper. The impact of the IGZO film thickness on the performance of TFTs is investigated. The threshold voltage, field-effect mobility, on and off drain current, and subthreshold swing are strongly affected by the thickness of the IGZO film. With the increase in film thickness, the threshold voltage shifted from positive to negative, which is related to the depletion layer formed by the oxygen absorbed on the surface. The field-effect mobility is affected by the film surface roughness, which is thickness dependent. Our results show that there is an optimum IGZO thickness, which ensures the best TFT electrical performance. The best result is from a 55-nm-thick IGZO TFT, which showed a field-effect mobility in the saturation region of 1.41 cm<sup>2</sup>/V·s, a threshold voltage of 1 V, a drain current on/off ratio of approximately 4.3 × 10<sup>7</sup>, a subthreshold swing of 384 mV/dec, and an off-current level lower than 1 pA.
    IEEE Transactions on Electron Devices 03/2011; · 2.32 Impact Factor

Institutions

  • 2009–2013
    • Nanyang Technological University
      • • Luminous Center of Excellence for Semiconductor Lighting and Displays
      • • School of Electrical and Electronic Engineering
      Singapore, Singapore
  • 2011
    • Sun Yat-Sen University Cancer Center
      Guangzhou, Guangdong Sheng, China
  • 2010
    • State Key Laboratory of Medical Genetics of China
      Changsha, Hunan, China
    • Bilkent University
      • Department of Electrical & Electronic Engineering
      Ankara, Ankara, Turkey
  • 2007–2010
    • Sun Yat-Sen University
      Guangzhou, Guangdong Sheng, China