3,102 research outputs found

    Detection of Sugar-Lectin Interactions by Multivalent Dendritic Sugar Functionalized Single-Walled Carbon Nanotubes

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    We show that single walled carbon nanotubes (SWNT) decorated with sugar functionalized poly (propyl ether imine) (PETIM) dendrimer is a very sensitive platform to quantitatively detect carbohydrate recognizing proteins, namely, lectins. The changes in electrical conductivity of SWNT in field effect transistor device due to carbohydrate - protein interactions form the basis of present study. The mannose sugar attached PETIM dendrimers undergo charge - transfer interactions with the SWNT. The changes in the conductance of the dendritic sugar functionalized SWNT after addition of lectins in varying concentrations were found to follow the Langmuir type isotherm, giving the concanavalin A (Con A) - mannose affinity constant to be 8.5 x 106 M-1. The increase in the device conductance observed after adding 10 nM of Con A is same as after adding 20 \muM of a non - specific lectin peanut agglutinin, showing the high specificity of the Con A - mannose interactions. The specificity of sugar-lectin interactions was characterized further by observing significant shifts in Raman modes of the SWNT.Comment: 12 pages, 3 figure

    Electro-deposition of gold nano-structures on gold Quartz Crystal Microbalance (QCM) electrodes for enhanced mercury vapour sensitivity in the presence of interferent gasses

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    Gold electrode quartz crystal microbalances (QCMs) were used as transducing platform to detect and sense elemental mercury (Hg) in gas phase. The enhanced sensitivity, resulting form the electro-deposition of gold nano-structures on the surface is shown to increase the response magnitude (RM) of the sensors in the presence of ammonia and humidity interference. The concentration of NH3 and H2O was varied in the range 590 to 1770mg/m3 and 4.2 to 10.4mg/m3, respectively. A constant gas flow of 200sccm, balanced in nitrogen was used as the carrier gas. The RM for Hg was enhanced by creating nanostructures on the sensorpsilas gold electrodes via electro-deposition of gold in a lead acetate electrolyte. The results presented are a critical step in the development of a cheap regenerable and reliable sensor for measuring Hg in the presence of interferents gases commonly found in industrial applications

    Development of nano-structured titanium oxide thin films using a gas carving technique

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    A method is developed for producing nano-structured titanium oxide thin films using H2 gas interaction with titanium thin film at a high temperature. These nano-structured thin films have been formed on a quartz crystal substrate. Titanium (Ti) thin films were deposited on the quartz crystal using a RF magnetron sputterer. The samples were placed in the oven at 500-800°C for 5 hours. The gas mixture of 1% H2 in N2 was introduced in the oven. The process of Ti annealing in the presence of H2 carves Ti films into nano-structure shapes. The process is a gas-solid interaction. Thin films were characterised using Scanning Electron Microscopes (SEM) and X-Ray Diffraction (XRD) technique. The nano structures formed have dimensions in a range of 25nm - 150nm obtained after gas carving

    Isospin effects on the energy of vanishing flow in heavy-ion collisions

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    Using the isospin-dependent quantum molecular dynamics model we study the isospin effects on the disappearance of flow for the reactions of 58Ni^{58}Ni + 58Ni^{58}Ni and 58Fe^{58}Fe +58Fe^{58}Fe as a function of impact parameter. We found good agreement between our calculations and experimentally measured energy of vanishing flow at all colliding geometries. Our calculations reproduce the experimental data within 5%(10%) at central (peripheral) geometries

    Reversible Pressure-Induced Amorphization in Solid C70 : Raman and Photoluminescence Study

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    We have studied single crystals of C70C_{70} by Raman scattering and photoluminescence in the pressure range from 0 to 31.1 GPa. The Raman spectrum at 31.1 GPa shows only a broad band similar to that of the amorphous carbon without any trace of the Raman lines of C70C_{70}. After releasing the pressure from 31.1 GPa, the Raman and the photoluminescence spectra of the recovered sample are that of the starting C70C_{70} crystal. These results indicate that the C70C_{70} molecules are stable upto 31.1 GPa and the amorphous carbon high pressure phase is reversible, in sharp contrast to the results on solid C60C_{60}. A qualitative explaination is suggested in terms of inter- versus intra-molecular interactions.Comment: To appear in Phys. Rev. Lett., 12 pages, RevTeX (preprint format), 3 figures available upon reques

    Rapidity distribution as a probe for elliptical flow at intermediate energies

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    Interplay between the spectator and participant matter in heavy-ion collisions is investigated within isospin dependent quantum molecular dynamics (IQMD) model in term of rapidity distribution of light charged particles. The effect of different types and size rapidity distributions is studied in elliptical flow. The elliptical flow patterns show important role of the nearby spectator matter on the participant zone. This role is further explained on the basis of passing time of the spectator and expansion time of the participant zone. The transition from the in-plane to out-of-plane is observed only when the mid-rapidity region is included in the rapidity bin, otherwise no transition occurs. The transition energy is found to be highly sensitive towards the size of the rapidity bin, while weakly on the type of the rapidity distribution. The theoretical results are also compared with the experimental findings and are found in good agreement.Comment: 8 figure

    Objective measurement for surgical skill evaluation

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    The purpose of this study was to identify measurable parameters that can be used to quantitatively assess psychomotor skills, specifically for surgical skills assessment. Sixteen participants were recruited from two groups: surgeon (N = 5) and non-surgeon (N = 11). Both groups underwent a psychomotor test using a custom developed ‘Green Target’ module which was designed using a virtual reality system. Six parameters were used to compare the psychomotor skills between the two groups. The results showed that surgeons outperformed the non-surgeons in five out of six parameters investigated and the difference was statistically significant. The average normalised comparison values for surgeons and non-surgeons for motion path accuracy, motion path precision, economy of movement, end-point accuracy and end-point precision were 0.13±0.12 and 0.17±0.12, 0.08±0.11 and 0.10±0.10, 3.76±1.76 and 4.08±2.24, 0.12±0.10 and 0.17±0.11, 0.04±0.10 and 0.07±s0.10 respectively, p < 0.05). These parameters can potentially be used to objectively assess the performance of surgical skill

    Global Environmental Flow Information for the Sustainable Development Goals

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    Environmental flows (EF) are an important component of Goal 6 (the ‘water goal’) of the Sustainable Development Goals (SDGs). Yet, many countries still do not have well-defined criteria on how to define EF. In this study, we bring together the International Water Management Institute’s (IWMI’s) expertise and previous research in this area to develop a new methodology to quantify EF at a global scale. EF are developed for grids (0.1 degree spatial resolution) for different levels of health (defined as environmental management classes [EMCs]) of river sections. Additionally, EF have been separated into surface water and groundwater components, which also helps in developing sustainable groundwater abstraction (SGWA) limits. An online tool has been developed to calculate EF and SGWA in any area of interest
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