1,433 research outputs found

    Monomolecular and thin polymer films: fabrication, characterization, applications, and models of wetting

    Get PDF
    A variety of chemically modified surfaces were synthesized and their molecular structures and reactivities were characterized. These interfaces include: (i) Monomolecular films of n-alkanoic acids (CH[subscript]3(CH[subscript]2)[subscript] nCOOH) and n-perfluorocarboxylic acids (CF[subscript]3(CF[subscript]2)[subscript] nCOOH) on silver; and (ii) calcichrome immobilized at an anion exchange polymer film. The monomolecular films were fabricated by the self-assembly method and characterized by optical ellipsometry, infrared reflection spectroscopy, and contact angle measurements. A comparison is given of the properties of these films with regard to composition, defectiveness, intermolecular environment, molecular orientation, wettability, and formation thermodynamics. As it is relevant to monolayer formation thermodynamics, the isoelectric point of the surface of evaporated silver films was determined by contact angle titration. Potential applications of these films are discussed;Monomolecular films as models of wetting are also examined in terms of van der Waals interactions at the macroscopic interfaces. Theoretical considerations of the effects of intermolecular forces on depth sensitivity of wetting and limiting contact angles of various systems are assessed;One of the synthesized interfaces has been applied as a Ca(II) optical sensor. The sensor was fabricated by electrostatic immobilization of calcichrome at an anion exchange polymer film. The structure and reactivity of this interface was characterized by ultraviolet-visible diffuse reflectance spectroscopy and infrared photoacoustic spectroscopy. Equations to determine the metal complex formation constant and acid dissociation constants of the immobilized reagent from diffuse reflectance spectra are developed. Possible causes affecting the reactivity of an immobilized indicator are discussed

    A Novel Design of Grooved Fibers for Fiber-Optic Localized Plasmon Resonance Biosensors

    Get PDF
    Bio-molecular recognition is detected by the unique optical properties of self-assembled gold nanoparticles on the unclad portions of an optical fiber whose surfaces have been modified with a receptor. To enhance the performance of the sensing platform, the sensing element is integrated with a microfluidic chip to reduce sample and reagent volume, to shorten response time and analysis time, as well as to increase sensitivity. The main purpose of the present study is to design grooves on the optical fiber for the FO-LPR microfluidic chip and investigate the effect of the groove geometry on the biochemical binding kinetics through simulations. The optical fiber is designed and termed as U-type or D-type based on the shape of the grooves. The numerical results indicate that the design of the D-type fiber exhibits efficient performance on biochemical binding. The grooves designed on the optical fiber also induce chaotic advection to enhance the mixing in the microchannel. The mixing patterns indicate that D-type grooves enhance the mixing more effectively than U-type grooves. D-type fiber with six grooves is the optimum design according to the numerical results. The experimental results show that the D-type fiber could sustain larger elongation than the U-type fiber. Furthermore, this study successfully demonstrates the feasibility of fabricating the grooved optical fibers by the femtosecond laser, and making a transmission-based FO-LPR probe for chemical sensing. The sensor resolution of the sensor implementing the D-type fiber modified by gold nanoparticles was 4.1 × 10−7 RIU, which is much more sensitive than that of U-type optical fiber (1.8 × 10−3 RIU)

    Hong Kong Renal Registry Report 2012

    Get PDF
    SummaryThis report examined the characteristics and trends of dialysis and renal transplant patients among the resident population of Hong Kong who were managed by hospitals or dialysis centers of the Hospital Authority, and accounted for approximately 95% of all patients receiving renal replacement therapies (RRTs) in the territory. Patients receiving RRTs solely in the private sector were not included in this report. Data trends from 1996 to 2011 are presented. In 2011, 1115 new patients were accepted into RRT programs, and the incident rate was 157 patients per million populations (pmp). An increasing trend was noted. The incident rate was 95.1 pmp at the commencement of the annual report in 1996. The point prevalence on December 31, 2012 was 8197 with a prevalence rate of 1152.5 pmp. Overall, there were 3573 patients (43.6%) on peritoneal dialysis (PD) and 1246 patients (15.2%) on hemodialysis (HD), and 3378 patients (41.2%) were living with a functioning renal transplant. The PD/HD ratio was 74.2:25.8. The “PD First” policy was continued. The overall mortality rate among RRT patients was 9.95 patients per 100 patient-years exposed. There was a decreasing trend in mortality among PD patients. Infection and cardiovascular complications were the most common causes of death. Renal transplant was the modality with the best survival rates. The 5 years cumulative patient survival rate for patients on transplant treatment was 89.6%, whereas the corresponding patient survival rates for PD and HD patients were 50.7% and 55.7%, respectively. More than 70% of RRT patients with reports on rehabilitation were active and had normal daily activities

    Measurement of the cross-section and charge asymmetry of WW bosons produced in proton-proton collisions at s=8\sqrt{s}=8 TeV with the ATLAS detector

    Get PDF
    This paper presents measurements of the W+→Ό+ÎœW^+ \rightarrow \mu^+\nu and W−→Ό−ΜW^- \rightarrow \mu^-\nu cross-sections and the associated charge asymmetry as a function of the absolute pseudorapidity of the decay muon. The data were collected in proton--proton collisions at a centre-of-mass energy of 8 TeV with the ATLAS experiment at the LHC and correspond to a total integrated luminosity of 20.2~\mbox{fb^{-1}}. The precision of the cross-section measurements varies between 0.8% to 1.5% as a function of the pseudorapidity, excluding the 1.9% uncertainty on the integrated luminosity. The charge asymmetry is measured with an uncertainty between 0.002 and 0.003. The results are compared with predictions based on next-to-next-to-leading-order calculations with various parton distribution functions and have the sensitivity to discriminate between them.Comment: 38 pages in total, author list starting page 22, 5 figures, 4 tables, submitted to EPJC. All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2017-13

    Search for new phenomena in final states with an energetic jet and large missing transverse momentum in pp collisions at √ s = 8 TeV with the ATLAS detector

    Get PDF
    Results of a search for new phenomena in final states with an energetic jet and large missing transverse momentum are reported. The search uses 20.3 fb−1 of √ s = 8 TeV data collected in 2012 with the ATLAS detector at the LHC. Events are required to have at least one jet with pT > 120 GeV and no leptons. Nine signal regions are considered with increasing missing transverse momentum requirements between Emiss T > 150 GeV and Emiss T > 700 GeV. Good agreement is observed between the number of events in data and Standard Model expectations. The results are translated into exclusion limits on models with either large extra spatial dimensions, pair production of weakly interacting dark matter candidates, or production of very light gravitinos in a gauge-mediated supersymmetric model. In addition, limits on the production of an invisibly decaying Higgs-like boson leading to similar topologies in the final state are presente

    Search for chargino-neutralino production with mass splittings near the electroweak scale in three-lepton final states in √s=13 TeV pp collisions with the ATLAS detector

    Get PDF
    A search for supersymmetry through the pair production of electroweakinos with mass splittings near the electroweak scale and decaying via on-shell W and Z bosons is presented for a three-lepton final state. The analyzed proton-proton collision data taken at a center-of-mass energy of √s=13  TeV were collected between 2015 and 2018 by the ATLAS experiment at the Large Hadron Collider, corresponding to an integrated luminosity of 139  fb−1. A search, emulating the recursive jigsaw reconstruction technique with easily reproducible laboratory-frame variables, is performed. The two excesses observed in the 2015–2016 data recursive jigsaw analysis in the low-mass three-lepton phase space are reproduced. Results with the full data set are in agreement with the Standard Model expectations. They are interpreted to set exclusion limits at the 95% confidence level on simplified models of chargino-neutralino pair production for masses up to 345 GeV

    Hybrid Surface-Enhanced Raman Scattering Substrate from Gold Nanoparticle and Photonic Crystal: Maneuverability and Uniformity of Raman Spectra

    Get PDF
    [[abstract]]A novel hybrid surface-enhanced Raman scattering (SERS) substrate based on Au nanoparticles decorated inverse opal (IO) photonic crystal (PhC) is presented. In addition to the enhancement contributed from Au nanoparticles, a desired Raman signal can be selectively further enhanced by appropriately overlapping the center of photonic bandgap of the IO PhC with the wavelength of the Raman signal. Furthermore, the lattice structure of the IO PhC provides excellent control of the distribution of Au nanoparticles to produce SERS spectra with high uniformity. The new design of SERS substrate provides extra maneuverability for ultra-high sensitivity sensor applications.[[notice]]èŁœæ­ŁćźŒ

    Quantifying the burden of disease due to premature mortality in Hong Kong using standard expected years of life lost

    Get PDF
    Plaß D, Chau PY, Thach T, et al. Quantifying the burden of disease due to premature mortality in Hong Kong using standard expected years of life lost. BMC Public Health. 2013;13(1): 863.Background To complement available information on mortality in a population Standard Expected Years of Life Lost (SEYLL), an indicator of premature mortality, is increasingly used to calculate the mortality-associated disease burden. SEYLL consider the age at death and therefore allow a more accurate view on mortality patterns as compared to routinely used measures (e.g. death counts). This study provides a comprehensive assessment of disease and injury SEYLL for Hong Kong in 2010. Methods To estimate the SEYLL, life-expectancy at birth was set according to the 2004 Global Burden of Disease study at 82.5 and 80 years for females and males, respectively. Cause of death data for 2010 were corrected for misclassification of cardiovascular and cancer causes. In addition to the baseline estimates, scenario analyses were performed using alternative assumptions on life-expectancy (Hong Kong standard life-expectancy), time-discounting and age-weighting. To estimate a trend of premature mortality a time-series analysis from 2001 to 2010 was conducted. Results In 2010 524,706.5 years were lost due to premature death in Hong Kong with 58.3% of the SEYLL attributable to male deaths. The three overall leading single causes of SEYLL were “trachea, bronchus and lung cancers”, “ischaemic heart disease” and “lower respiratory infections” together accounting for about 29% of the overall SEYLL. Further, self-inflicted injuries (5.6%; ranked 5) and liver cancer (4.9%; ranked 7) were identified as important causes not adequately captured by classical mortality measures. Scenario analyses highlighted that by using a 3% time-discount rate and non-uniform age-weights the SEYLL dropped by 51.6%. Using Hong Kong’s standard life-expectancy values resulted in an overall increase of SEYLL by 10.8% as compared to the baseline SEYLL. Time-series analysis indicates an overall increase of SEYLL by 6.4%. In particular, group I (communicable, maternal, perinatal and nutritional) conditions showed highest increases with SEYLL-rates per 100,000 in 2010 being 1.4 times higher than 2001. Conclusions The study stresses the mortality impact of diseases and injuries that occur in earlier stages of life and thus presents the SEYLL measure as a more sensitive indicator compared to classical mortality indicators. SEYLL provide useful additional information and supplement available death statistics

    Novel Method for Differentiating Histological Types of Gastric Adenocarcinoma by Using Confocal Raman Microspectroscopy

    Get PDF
    [[abstract]]Gastric adenocarcinoma, a single heterogeneous disease with multiple epidemiological and histopathological characteristics, accounts for approximately 10% of cancers worldwide. It is categorized into four histological types: papillary adenocarcinoma (PAC), tubular adenocarcinoma (TAC), mucinous adenocarcinoma (MAC), and signet ring cell adenocarcinoma (SRC). Effective differentiation of the four types of adenocarcinoma will greatly improve the treatment of gastric adenocarcinoma to increase its five-year survival rate. We reported here the differentiation of the four histological types of gastric adenocarcinoma from the molecularly structural viewpoint of confocal Raman microspectroscopy. In total, 79 patients underwent laparoscopic or open radical gastrectomy during 2008–2011: 21 for signet ring cell carcinoma, 21 for tubular adenocarcinoma, 14 for papillary adenocarcinoma, 6 for mucinous carcinoma, and 17 for normal gastric mucosas obtained from patients underwent operation for other benign lesions. Clinical data were retrospectively reviewed from medical charts, and Raman data were processed and analyzed by using principal component analysis (PCA) and linear discriminant analysis (LDA). Two-dimensional plots of PCA and LDA clearly demonstrated that the four histological types of gastric adenocarcinoma could be differentiated, and confocal Raman microspectroscopy provides potentially a rapid and effective method for differentiating SRC and MAC from TAC or PAC[[notice]]èŁœæ­ŁćźŒ

    Measurement of the View the tt production cross-section using eÎŒ events with b-tagged jets in pp collisions at √s = 13 TeV with the ATLAS detector

    Get PDF
    This paper describes a measurement of the inclusive top quark pair production cross-section (σttÂŻ) with a data sample of 3.2 fb−1 of proton–proton collisions at a centre-of-mass energy of √s = 13 TeV, collected in 2015 by the ATLAS detector at the LHC. This measurement uses events with an opposite-charge electron–muon pair in the final state. Jets containing b-quarks are tagged using an algorithm based on track impact parameters and reconstructed secondary vertices. The numbers of events with exactly one and exactly two b-tagged jets are counted and used to determine simultaneously σttÂŻ and the efficiency to reconstruct and b-tag a jet from a top quark decay, thereby minimising the associated systematic uncertainties. The cross-section is measured to be: σttÂŻ = 818 ± 8 (stat) ± 27 (syst) ± 19 (lumi) ± 12 (beam) pb, where the four uncertainties arise from data statistics, experimental and theoretical systematic effects, the integrated luminosity and the LHC beam energy, giving a total relative uncertainty of 4.4%. The result is consistent with theoretical QCD calculations at next-to-next-to-leading order. A fiducial measurement corresponding to the experimental acceptance of the leptons is also presented
    • 

    corecore