03132nas a2200181   4500008004100000022001400041245011800055210006900173260011000242300001600352490000600368520237100374100001902745700001702764700001802781700001902799856013202818       2016                        eng d  a2046-206900aBroad spectrum photon responsive, paramagnetic beta-NaGdF4: Yb3+, Er3+ - mesoporous anatase titania nanocomposite0 aBroad spectrum photon responsive paramagnetic betaNaGdF4 Yb3 Er3  aTHOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLANDbROYAL SOC CHEMISTRYcMAY  a53504-535180 v63 a<p>Herein, we report a novel single multifunctional platform based on broad-spectrum photoactive beta-NaGdF4:18% Yb3+, 2% Er3+ and mesoporous anatase TiO2 for enhanced energy and simultaneous biomedical applications. Currently, the photoactive materials for solar energy harvesting applications have limitations in their efficiency due to their narrow photon absorption spectrum. The upconversion phosphor beta-NaGdF4: 18% Yb3+, 2% Er3+ nanorods collect and harvest the NIR photons (similar to 980 nm) of sunlight and transform them into visible light via anti-Stokes emission (lambda(em) similar to 521 and similar to 540 nm), and the photoactive mesoporous anatase TiO2 (mTiO(2)) utilizes UV and weak visible photons, thus the composite forms a broad spectrum photon-capture system and improved power conversion efficiency for enhanced applications in photocatalysis, and dye sensitized solar cells (DSSCs). The photocatalytic activity of the nanocomposite showed an improvement in comparison to the mTiO(2) for the degradation of various dyes. In addition, the photocurrent density and solar cell efficiency of the nanocomposites showed an improvement by similar to 24% and similar to 17% respectively, over mTiO(2). The beta-NaGdF4: Yb3+, Er3+/mTiO(2) nanocomposite exhibits a strong paramagnetic signal (chi similar to 6.45 x 10(-5) emu g(-1) Oe(-1)). The nuclear magnetic resonance (NMR) measurements showed large longitudinal T1 relaxivity (r(1) = 7.09 s(-1) mM(-1)) and magnetic resonance imaging showed enhanced T-1-weighted MRI images with increased concentrations of beta-NaGdF4: Yb3+, Er3+/mTiO(2) nanocomposite making them suitable for simultaneous magnetoresonance imaging. In addition, this composite system can also be used as a NIR triggered drug delivery system and in biomedical applications. Moreover, mesoporous TiO2 is expected to increase the photocatalytic active sites, dye, and absorption, and drug loading capacity. The as-designed multifunctional beta-NaGdF4:Yb3+, Er3+/mTiO(2) nanocomposite possessed simultaneous multiple discrete functionalities with excellent luminescence properties, intrinsic paramagnetism, biocompatibility, improved photocatalytic activity, and solar cell efficiency. This work provides a promising system to utilize NIR light, which will contribute to efficient photon harvesting and biological applications.</p>1 aPadhye, Preeti1 aSadhu, Subha1 aMalik, Monika1 aPoddar, Pankaj  uhttps://library.ncl.res.in/content/broad-spectrum-photon-responsive-paramagnetic-beta-nagdf4-yb3-er3-mesoporous-anatase-titania04056nas a2200157   4500008004100000245009000041210006900131260000800200300001400208490000600222520349800228100001803726700001903744700001903763856011603782       2019                        eng d00a Downconversion luminescence-based nanosensor for label-free detection of explosives 0 aDownconversion luminescencebased nanosensor for labelfree detect  cFEB  a4259-42680 v43 a<p>We report <span class="hitHilite">a</span> selective and sensitive <span class="hitHilite">nanosensor</span> probe based on polyethylenimine (PEI)-capped downconverting nanophosphors beta-NaYF4:Gd3+, Tb3+@PEI <span class="hitHilite">for</span> <span class="hitHilite">the</span> <span class="hitHilite">detection</span> <span class="hitHilite">of</span> 2,4,6-trinitrotoluene (TNT), <span class="hitHilite">both</span> in water and buffer media. These downconverting phosphors were synthesized via <span class="hitHilite">a</span> hydrothermal route and are known to show excellent chemical, thermal, and photostability. They emit sharp emission peaks centered at similar to 488, 544, 584, and 619 nm, among which <span class="hitHilite">the</span> peak at similar to 544 nm was remarkably quenched (similar to 90%) <span class="hitHilite">by</span> <span class="hitHilite">the</span> addition <span class="hitHilite">of</span> TNT without giving any new emission peak. <span class="hitHilite">The</span> sensing mechanism is based on <span class="hitHilite">the</span> <span class="hitHilite">formation</span> <span class="hitHilite">of</span> <span class="hitHilite">a</span> Meisenheimer <span class="hitHilite">complex</span> between <span class="hitHilite">the</span> <span class="hitHilite">electron</span>-rich amine-functionalized beta-NaYF4:Gd3+, Tb3+ nanophosphors and <span class="hitHilite">electron</span>-deficient TNT molecule, which was prominently visualized <span class="hitHilite">by</span> <span class="hitHilite">the</span> change in <span class="hitHilite">the</span> color <span class="hitHilite">of</span> <span class="hitHilite">the</span> solution <span class="hitHilite">from</span> whitish to brownish yellow, enabling visual <span class="hitHilite">detection</span>, followed <span class="hitHilite">by</span> luminescence resonance energy <span class="hitHilite">transfer</span> between <span class="hitHilite">the</span> nanophosphors and <span class="hitHilite">the</span> <span class="hitHilite">complex</span>. <span class="hitHilite">A</span> linear range <span class="hitHilite">for</span> TNT <span class="hitHilite">detection</span> was obtained <span class="hitHilite">from</span> 0.1 to 300 mu M <span class="hitHilite">with</span> <span class="hitHilite">a</span> limit <span class="hitHilite">of</span> <span class="hitHilite">detection</span> <span class="hitHilite">as</span> low <span class="hitHilite">as</span> 119.9 nM. This method displayed excellent selectivity toward TNT over other nitroaromatic compounds, which had no influence on <span class="hitHilite">the</span> <span class="hitHilite">detection</span>. Moreover, various other classes <span class="hitHilite">of</span> analytes, viz., amino acids, pesticides, and sugars, did not quench <span class="hitHilite">the</span> luminescence intensity <span class="hitHilite">of</span> <span class="hitHilite">the</span> nanophosphors. This developed <span class="hitHilite">nanosensor</span> probe possesses high, stable fluorescence brightness and capability <span class="hitHilite">for</span> <span class="hitHilite">the</span> selective and sensitive on-site recognition <span class="hitHilite">of</span> TNT molecules in aqueous media, avoiding complicated strategies and instruments. Thus, this work promises to pave ways to many applications in <span class="hitHilite">the</span> <span class="hitHilite">detection</span> <span class="hitHilite">of</span> ultratrace analytes.</p>
1 aMalik, Monika1 aPadhye, Preeti1 aPoddar, Pankaj  uhttps://library.ncl.res.in/content/downconversion-luminescence-based-nanosensor-label-free-detection-explosives02207nas a2200301   4500008004100000245012300041210006900164260000800233300000900241490000700250520125500257653001301512653002601525653002001551653001501571653000901586653001201595653002101607100001701628700001601645700001801661700001801679700001801697700001901715700002301734700002001757856012801777       2020                        eng d00aStudy of interfacial adhesion between nickel-titanium shape memory alloy and a polymer matrix by laser surface pattern0 aStudy of interfacial adhesion between nickeltitanium shape memor  cMAR  a21720 v103 a<p>The aim of this article is to investigate the interfacial adhesion of Ni-Ti shape memory alloy with a polymer matrix of Poly (methyl methacrylate) (PMMA). The surface pattern on Ni-Ti plates was channeled by a solid state laser machine. The laser machine allows for creating channels on the Ni-Ti surface for infiltration of the PMMA matrix, which could be attached as an intra-surface locking pattern to the Ni-Ti surface. The influence of the PMMA matrix on the surface of the NiTi plate was evaluated by thermomechanical analysis (TMA) and dynamic mechanical analysis (DMA). The surface characterization was carried out by an optical microscope on the PMMA/NiTi composite after mechanical testing. During mechanical testing, the polymer displays the multiple cracks in the longitudinal direction that result in slipping and fracture. TMA and DMA analyses were performed on the Ni-Ti- and PMMA-coated Ni-Ti ribbon to observe elasticity and the storage modulus for both samples. Better adhesion than 80 % was observed in the Ni-Ti surface, in the laser surface pattern, in comparison to the free plain surface. However, the polymer acts as mechanical backing that caused a reduction in the shape-memory properties of the composite material.</p>
10aadhesion10amechanical properties10aNiTi composites10aNiTi plate10aPMMA10aPolymer10asurface features1 aSamal, Sneha1 aTyc, Ondrej1 aHeller, Ludek1 aSittner, Petr1 aMalik, Monika1 aPoddar, Pankaj1 aCatauro, Michelina1 aBlanco, Ignazio  uhttps://library.ncl.res.in/content/study-interfacial-adhesion-between-nickel-titanium-shape-memory-alloy-and-polymer-matrix01873nas a2200169   4500008004100000022001400041245014100055210006900196260000800265300001400273490000700287520121800294100002601512700001801538700001901556856012801575       2021                        eng d  a1144-054600aRaman spectroscopy-based sensitive, fast and reversible vapour phase detection of explosives adsorbed on metal-organic frameworks UiO-670 aRaman spectroscopybased sensitive fast and reversible vapour pha  cAPR  a7145-71530 v453 a<p>In this work, we report highly sensitive, selective, rapid, and reversible detection of explosive molecules in the vapour phase, adsorbed on metal-organic frameworks (MOFs) under ambient laboratory conditions. The sensing is based on the quenching of the Raman intensity of a zirconium-based MOF, Zr6O4(OH)(4)(dcppy)(6) (MOF 1, UiO-67-dcppy; dcppy is 2-phenylpyridine-5,4'-dicarboxylate), where 50% of the signal quenches swiftly within similar to 5 s of its exposure to trinitrophenol (TNP) vapours, while 90% of the Raman signal was quenched in 30 s. The high surface area of porous MOFs provides increased adsorption of various nitro analytes. The quenching of Raman peaks resulted from the pi-pi interactions of the analytes with the benzene ring of the MOF. The sensors have also been proven to be reversible and stable by mild heat treatment (80 degrees C for 5 min). These notable results using Raman spectroscopy point to a new and important approach towards explosive sensing using metal-organic frameworks considering their vast versatility. This work emphasizes the importance of a non-invasive and non-destructive technique that can be used to develop handheld vapour phase explosive detectors.</p>1 aBishwas, Mousumi, Sen1 aMalik, Monika1 aPoddar, Pankaj  uhttps://library.ncl.res.in/content/raman-spectroscopy-based-sensitive-fast-and-reversible-vapour-phase-detection-explosives