01963nas a2200181 4500008004100000022001400041245013500055210006900190260011000259300001600369490000600385520119500391100001801586700002001604700001401624700001901638856012401657 2013 eng d a2046-206900aStatic and dynamic magnetic properties and effect of surface chemistry on the morphology and crystallinity of DyCrO3 nanoplatelets0 aStatic and dynamic magnetic properties and effect of surface che aTHOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLANDbROYAL SOC CHEMISTRYcOCT a26427-264320 v33 a

In this contribution, the structural and magnetic properties of DyCrO3 nanoplatelets, synthesized by a hydrolytic sol-gel method, have been investigated. The crystalline phase of DyCrO3 was attained at the decomposition temperature of 800 degrees C for citric acid and oxalic acid, respectively and their structural analysis indicates a distorted orthorhombic perovskite structure of the DyCrO3 nanoplatelets. The dc-magnetization curve shows the Neel temperature of similar to 144 and similar to 146 K for DyCrO3 nanoplatelets synthesized using citric acid (DCO (C)) and oxalic acid (DCO (O)), respectively. In addition, DCO (O) shows weak anomalies at similar to 22 and similar to 6 K in the zero-field-cooled and field-cooled magnetization curves. Below the Neel temperature, DCO (C) and DCO (O) exhibit cross-over from positive to negative magnetization at similar to 143 and similar to 145 K, respectively. This was attributed to a Dy3+-Cr3+ interaction, which resulted in a weak ferromagnetic coupling (seen as a small opening in the M-H curves). The low temperature transition observed at similar to 6 K can be assigned to the onset of Dy3+-Dy3+ antiferromagnetic interaction.

1 aGupta, Preeti1 aBhargava, Richa1 aDas, Raja1 aPoddar, Pankaj uhttps://library.ncl.res.in/content/static-and-dynamic-magnetic-properties-and-effect-surface-chemistry-morphology-and-003008nas a2200241 4500008004100000022001400041245019800055210006900253260009100322300001200413490000600425520201000431100002102441700002202462700002102484700001802505700002302523700002402546700001902570700002202589700002702611856012802638 2014 eng d a1932-620300aSynthesis, characterization and in vitro study of biocompatible cinnamaldehyde functionalized magnetite nanoparticles (CPGF Nps) for hyperthermia and drug delivery applications in breast cancer0 aSynthesis characterization and in vitro study of biocompatible c a1160 BATTERY STREET, STE 100, SAN FRANCISCO, CA 94111 USAbPUBLIC LIBRARY SCIENCEcSEP ae1073150 v93 a

Cinnamaldehyde, the bioactive component of the spice cinnamon, and its derivatives have been shown to possess anticancer activity against various cancer cell lines. However, its hydrophobic nature invites attention for efficient drug delivery systems that would enhance the bioavailability of cinnamaldehyde without affecting its bioactivity. Here, we report the synthesis of stable aqueous suspension of cinnamaldehyde tagged Fe3O4 nanoparticles capped with glycine and pluronic polymer (CPGF NPs) for their potential application in drug delivery and hyperthermia in breast cancer. The monodispersed superparamagnetic NPs had an average particulate size of similar to 20 nm. TGA data revealed the drug payload of similar to 18%. Compared to the free cinnamaldehyde, CPGF NPs reduced the viability of breast cancer cell lines, MCF7 and MDAMB231, at lower doses of cinnamaldehyde suggesting its increased bioavailability and in turn its therapeutic efficacy in the cells. Interestingly, the NPs were non-toxic to the non-cancerous HEK293 and MCF10A cell lines compared to the free cinnamaldehyde. The novelty of CPGF nanoparticulate system was that it could induce cytotoxicity in both ER/PRpositive/Her2 negative (MCF7) and ER/PRnegative/Her2 negative (MDAMB231) breast cancer cells, the latter being insensitive to most of the chemotherapeutic drugs. The NPs decreased the growth of the breast cancer cells in a dose-dependent manner and altered their migration through reduction in MMP-2 expression. CPGF NPs also decreased the expression of VEGF, an important oncomarker of tumor angiogenesis. They induced apoptosis in breast cancer cells through loss of mitochondrial membrane potential and activation of caspase-3. Interestingly, upon exposure to the radiofrequency waves, the NPs heated up to 41.6 degrees C within 1 min, suggesting their promise as a magnetic hyperthermia agent. All these findings indicate that CPGF NPs prove to be potential nano-chemotherapeutic agents in breast cancer.

1 aWani, Kirtee, D.1 aKadu, Brijesh, S.1 aMansara, Prakash1 aGupta, Preeti1 aDeore, Avinash, V.1 aChikate, Rajeev, C.1 aPoddar, Pankaj1 aDhole, Sanjay, D.1 aKaul-Ghanekar, Ruchika uhttps://library.ncl.res.in/content/synthesis-characterization-and-vitro-study-biocompatible-cinnamaldehyde-functionalized-002161nas a2200229 4500008004100000022001400041245016000055210006900215260000900284300001100293490000700304520132000311653001801631653002201649653002701671653002201698653002301720100001801743700002001761700001901781856013101800 2015 eng d a0022-372700aColossal increase in negative magnetization, exchange bias and coercivity in samarium chromite due to a strong coupling between Sm3+-Cr3+ spins sublattices0 aColossal increase in negative magnetization exchange bias and co cJAN  a0250040 v483 a

We report giant temperature dependent negative magnetization (magnetization reversal) along with a large exchange bias and large coercivity in SmCrO3. The static magnetization measurements show the negative magnetization below similar to 192 K, due to competition between the external field, thermal activation energy and antiparallel Sm3+-Cr3+ spin interaction. At further lower temperatures, Sm3+ spins show an increased alignment due to the internal induced field of Cr3+ spins with minimum magnetization similar to - 0.037 emu g(-1). The temperature dependent exchange bias shows non-monotonic behavior. At 35 K, the exchange bias ceases to exist due to the orientation of Sm3+ moments with respect to canted Cr3+ moments. The crossover temperature decreases from similar to 191 K at 100 Oe to similar to 153 K at 250 Oe. The training effect further confirms the exchange bias in SmCrO3. The dynamic magnetization measurements exhibit anomalies around spin reorientation transition (T-SR similar to 34 K) and Neel transition (T-N similar to 192 K) which is consistent with static measurement and no frequency dependence was observed. The room temperature Raman spectra of SmCrO3 show peaks at similar to 364, similar to 375 and similar to 456 cm(-1) suggesting O-Cr-O bending modes within the octahedral.

10aexchange bias10amultiferroics etc10anegative magnetization10asamarium chromite10aspin reorientation1 aGupta, Preeti1 aBhargava, Richa1 aPoddar, Pankaj uhttps://library.ncl.res.in/content/colossal-increase-negative-magnetization-exchange-bias-and-coercivity-samarium-chromite-due02359nas a2200157 4500008004100000022001400041245012700055210006900182260007100251300001400322490000700336520169100343100001802034700001902052856013002071 2015 eng d a0020-166900aTemperature and magnetic field-assisted switching of magnetization and observation of exchange bias in YbCrO3 nanocrystals0 aTemperature and magnetic fieldassisted switching of magnetizatio a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcOCT a9509-95160 v543 a

In this paper, we demonstrate an interesting feature in YbCrO3 (YCO) nanocrystals, in which the material shows temperature and external magnetic field-assisted switching (a complete sign reversal) of zero field cooled magnetization (M-ZFC) and observation of exchange bias (EB) as a result of competing spin interaction at low temperature. This feature can be applied in nonvolatile memories, where, simply by changing the magnitude of the H-ext and T, the polarity of the magnetization can be switched between negative and positive. We also observed negative magnetization in YCO. Our results showed that, below its Neel temperature (T-N approximate to 119 K), the M-ZFC crosses over to negative sign for H < 1000 Oe. At 60 K, YCO showed a significant negative M-ZFC approximate to -0.05 emu/g (at 100 Oe) due to the competing effects of Yb3+, Cr3+ spins, thermal activation energy, and Hext. At further lower temperatures, the M-ZFC showed a crossover to positive values, and the crossover temperature showed the dependence on H-ext (similar to 19 K for 100 Oe curve). The YCO also showed H-ext T-dependent H-EB, which changed its sign with T. The observed T-dependent sign reversal in the EB was closely associated with the sign reversal of M-ZFC. The symmetric shift in field-cooled isothermal hysteresis curves confirmed that the observed EB was not due to the unsaturated minor loop. The training cycle further confirmed that the H-EB value decreased to similar to 2% of the initial value of observed EB, which was very small compared to the observed H-EB in YCO, which indicated stable spin configuration at the locally formed ferromagnetic/antiferromagnetic interface.

1 aGupta, Preeti1 aPoddar, Pankaj uhttps://library.ncl.res.in/content/temperature-and-magnetic-field-assisted-switching-magnetization-and-observation-exchange-001665nas a2200157 4500008004100000022001400041245012600055210006900181260011000250300001600360490000600376520095600382100001801338700001901356856013201375 2015 eng d a2046-206900aUsing Raman and dielectric spectroscopy to elucidate the spin phonon and magnetoelectric coupling in DyCrO3 nanoplatelets0 aUsing Raman and dielectric spectroscopy to elucidate the spin ph aTHOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLANDbROYAL SOC CHEMISTRYcJAN a10094-101010 v53 a

In this study, we report the phonon-mode assignment of DyCrO3 nanoplatelets by Raman spectroscopy. The temperature dependent Raman studies indicate the shift in the phonon frequency of most intense modes of DyCrO3 and the observed change in Raman line-width is correlated with the spin-phonon coupling. The impedance spectroscopy reveals anomalies in the dielectric constant vs. temperature curve in the proximity of the magnetic transitions, thereby hinting towards possible weak magnetoelectric coupling in DyCrO3 nanoplatelets. For the first time, UV-vis absorption spectroscopy and photocatalytic activity of DyCrO3 nanoplatelets have been reported. The optical absorption spectrum gives the band gap similar to 2.8 eV for DyCrO3 nanoplatelets suggesting them as a good candidate for studying photocatalytic activity. The DyCrO3 nanoplatelets showed an efficient photocatalytic activity by degrading 65% methyl orange after 8 h irradiation.

1 aGupta, Preeti1 aPoddar, Pankaj uhttps://library.ncl.res.in/content/using-raman-and-dielectric-spectroscopy-elucidate-spin-phonon-and-magnetoelectric-coupling-002154nas a2200145 4500008004100000245007200041210006900113260000800182300001600190490000600206520165800212100001801870700001901888856010101907 2016 eng d00aStudy of magnetic and thermal properties of SmCrO3 polycrystallites0 aStudy of magnetic and thermal properties of SmCrO3 polycrystalli cAUG a82014-820230 v63 aIn the present work, we have studied the magnetic and thermal properties of sol gel derived samarium chromite (SCO) polycrystallites. The magnetic measurements of SCO polycrystallites show a characteristic antiferromagnetic transition T-N similar to 190 K and spin reorientation temperature T-SR similar to 33 K, which is in the region of interest to study a possible magnetocaloric effect (MCE). The isothermal magnetic entropy change (Delta S-M) is estimated by an indirect method from the isothermal magnetization curves measured in this temperature range. The SCO polycrystallites possesses both inverse (positive) and normal (negative) MCE at and above around the spin reorientation transition (TSR) with Delta S-M(max) M values of similar to -24 x 10(-2) & 13 x 10(-2) J kg(-1) K-1, respectively. The SCO also shows another normal (negative) MCE peak around its Neel transition (T-N) with -Delta S-M(max) M similar to 11 x 10(-2) J kg(-1) K-1. The presence of two successive MCE peaks in SCO in the temperature range of 3-50 K, leads to an similar to 47 K operating temperature window with one thermodynamic cycle. In addition, the low temperature heat capacity (C-P) measurements of SCO polycrystallites reveal a lambda-shaped peak at T-N which is associated with a conventional second- order, paramagnetic to antiferromagnetic (AFM), phase transition. The temperature and magnetic field dependence of the specific heat capacity was studied and analyzed to estimate the adiabatic temperature change (Delta T-ad). In addition the C-P vs. T curve in SCO also shows a weak anomaly around the similar to T-SR along with a Schottky anomaly below 10 K.1 aGupta, Preeti1 aPoddar, Pankaj uhttps://library.ncl.res.in/content/study-magnetic-and-thermal-properties-smcro3-polycrystallites02472nas a2200157 4500008004100000245026000041210006900301260000800370300001600378490000600394520173500400100001702135700001802152700001902170856012502189 2017 eng d00aPhysical mechanism behind enhanced photoelectrochemical and photocatalytic properties of superhydrophilic assemblies of 3D-TiO2 microspheres with arrays of oriented, single-crystalline TiO2 nanowires as building blocks deposited on fluorine-doped tin oxid0 aPhysical mechanism behind enhanced photoelectrochemical and phot cMAR a11202-112110 v93 aIn comparison to the one-dimensional (1D) semiconductor nanostructures, the hierarchical, three-dimensional (3D) microstructures, composed of the arrays of 1D nanostructures as building blocks, show quite unique physicochemical properties due to efficient photon capture and enhanced surface to volume ratio, which aid in advancing the performance of various optoelectronic devices. In this contribution, we report the fabrication of surfactant-free, radially assembled, 3D titania (rutile-phase) microsphere arrays (3D-TMSAs) composed of bundles of single-crystalline titania nanowires (NWs) directly on fluorine-doped conducting oxide (FTO) substrates with tunable architecture. The effects of growth parameters on the morphology of the 3D-TMSAs have been studied thoroughly. The 3D-TMSAs grown on the FTO-substrate showed superior photon-harvesting owing to the increase in light-scattering. The photocatalytic and photon to electron conversion efficiency of dye sensitized solar cells (DSSC), where the optimized 3D-TMSAs were used as an anode, showed around 44% increase in the photoconversion efficiency compared to that of Degussa P-25 as a result of the synergistic effect of higher surface area and enhanced photon scattering probability. The TMSA film showed superhydrophilicity without any prior UV irradiation. In addition, the presence of bundles of almost parallel NWs led to the formation of arrays of microcapacitors, which showed stable dielectric performance. The fabrication of single-crystalline, oriented, self-assembled TMSAs with bundles of titania nanowires as their building blocks deposited on transparent conducting oxide (TCO) substrates has vast potential in the area of photoelectrochemical research.1 aSadhu, Subha1 aGupta, Preeti1 aPoddar, Pankaj uhttps://library.ncl.res.in/content/physical-mechanism-behind-enhanced-photoelectrochemical-and-photocatalytic-properties01319nas a2200205 4500008004100000245006100041210005900102260000800161300001000169490000800179520065400187100002900841700002900870700002700899700001800926700001900944700003200963700002700995856009101022 2018 eng d00aPolycrystalline MnGe2 thin films on InAs(001) substrates0 aPolycrystalline MnGe2 thin films on InAs001 substrates cJUL a38-410 v6573 aWe report on the growth of MnGe2 thin films on InAs(001) substrates using radio frequency-magnetron cosputtering. Polycrystalline thin films were obtained at a substrate temperature of 353 K. X-ray diffractometry was used to identify the tetragonal MnGe2 phase (space group 14/mcm). Measurements of the magnetic field and temperature dependence of the magnetization revealed that the MnGe2 thin films are ferromagnetic with a magnetization of 280 kAm(-1) and a Curie temperature of 62 K. Additionally, an antiferromagnetic component is observed at low temperatures, which may arise atomic disorder at the grain boundaries between MnGe2 crystallites.1 aGutierrez-Naranjo, David1 aHolguin-Momaca, Jose, T.1 aSolis-Canto, Oscar, O.1 aGupta, Preeti1 aPoddar, Pankaj1 aMagana, Francisco, Espinosa1 aOlive-Mendez, Sion, F. uhttps://library.ncl.res.in/content/polycrystalline-mnge2-thin-films-inas001-substrates01363nas a2200205 4500008004100000022001400041245009300055210006900148260000800217300001200225490000700237520068100244100002100925700001700946700001800963700001800981700001800999700001901017856012101036 2022 eng d a2159-685900aLuminescence turn-off detection of metal ions and explosives using graphene quantum dots0 aLuminescence turnoff detection of metal ions and explosives usin cAPR a168-1740 v123 a

Green luminescent graphene quantum dots (GQDs) obtained from combustion of white printing paper were used for detection of fourteen different metal ions and six different explosives in an aqueous medium. These were obtained using a microwave-assisted synthesis process. After optimizing the experimental conditions (pH 6; quantum yield (QY) similar to 38.2%), a sensitive sensing system was developed to detect explosives and free residual metal ions in the environment based on fluorescence quenching of GQDs. The as-synthesized GQDs, as a sensing system, is most sensitive for Cu2+ ion and 2,4-DNP with a detection limit of 0.62 mu M and 0.50 mu M, respectively.

1 aJyotsna, Shubhra1 aSadhu, Subha1 aSharma, Vinay1 aGupta, Preeti1 aSharma, Geeta1 aPoddar, Pankaj uhttps://library.ncl.res.in/content/luminescence-turn-detection-metal-ions-and-explosives-using-graphene-quantum-dots