35 research outputs found
Temperature and Magnetic Field-Assisted Switching of Magnetization and Observation of Exchange Bias in YbCrO<sub>3</sub> Nanocrystals
In
this paper, we demonstrate an interesting feature in YbCrO<sub>3</sub> (YCO) nanocrystals, in which the material shows temperature and
external magnetic field-assisted switching (a complete sign reversal)
of zero field cooled magnetization (<i>M</i><sub>ZFC</sub>) 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 <i>H</i><sub>ext</sub> and <i>T</i>, 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 NeÌel temperature (<i>T</i><sub>N</sub> â
119 K), the <i>M</i><sub>ZFC</sub> crosses over to negative
sign for <i>H</i> < 1000 Oe. At 60 K, YCO showed a significant
negative <i>M</i><sub>ZFC</sub> â â0.05 emu/g
(at 100 Oe) due to the competing effects of Yb<sup><i>3+</i></sup>, Cr<sup>3+</sup> spins, thermal activation energy, and <i>H</i><sub>ext</sub>. At further lower temperatures, the <i>M</i><sub>ZFC</sub> showed a crossover to positive values, and
the crossover temperature showed the dependence on <i>H</i><sub>ext</sub> (âŒ19 K for 100 Oe curve). The YCO also showed <i>H</i><sub>ext</sub> and <i>T</i>-dependent <i>H</i><sub>EB</sub>, which changed its sign with <i>T</i>. The observed <i>T</i>-dependent sign reversal in the
EB was closely associated with the sign reversal of <i>M</i><sub>ZFC</sub>. 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 <i>H</i><sub>EB</sub> value decreased to âŒ2% of the initial
value of observed EB, which was very small compared to the observed <i>H</i><sub>EB</sub> in YCO, which indicated stable spin configuration
at the locally formed ferromagnetic/antiferromagnetic interface
Physical Mechanism Behind Enhanced Photoelectrochemical and Photocatalytic Properties of Superhydrophilic Assemblies of 3D-TiO<sub>2</sub> Microspheres with Arrays of Oriented, Single-Crystalline TiO<sub>2</sub> Nanowires as Building Blocks Deposited on Fluorine-Doped Tin Oxide
In 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
Synthesis of 2âNitroglycals from Glycals Using the Tetrabutylammonium NitrateâTrifluoroacetic AnhydrideâTriethylamine Reagent System and Base-Catalyzed Ferrier Rearrangement of Acetylated 2âNitroglycals
A reagent
system comprising tetrabutylammonium nitrateâtrifluoroacetic
anhydrideâtriethylamine has been developed for the synthesis
of 2-nitroglycals from various protected glycals. The base-catalyzed
Ferrier rearrangement on tri-<i>O</i>-acetylated 2-nitroglycals
has been reported for the first time. Reactivity of these nitroacetates
and associated selectivity has been examined, and some of the products
have been converted into 2,3-diamino-2,3-dideoxyglycosides and methyl <i>N</i>-acetyl-d-lividosaminide
Synthesis of 2âNitroglycals from Glycals Using the Tetrabutylammonium NitrateâTrifluoroacetic AnhydrideâTriethylamine Reagent System and Base-Catalyzed Ferrier Rearrangement of Acetylated 2âNitroglycals
A reagent
system comprising tetrabutylammonium nitrateâtrifluoroacetic
anhydrideâtriethylamine has been developed for the synthesis
of 2-nitroglycals from various protected glycals. The base-catalyzed
Ferrier rearrangement on tri-<i>O</i>-acetylated 2-nitroglycals
has been reported for the first time. Reactivity of these nitroacetates
and associated selectivity has been examined, and some of the products
have been converted into 2,3-diamino-2,3-dideoxyglycosides and methyl <i>N</i>-acetyl-d-lividosaminide
Inhibition of α-Glucosidase Enzyme by âClickâ Inspired Pharmacophore Framework 1,3,4-Thiadiazole-1,2,3-Triazole Hybrids - supplementary material
checkCIF/PLATON reports
 1H-NMR spectra of all the compoundsÂ
 13C-NMR spectra of all the compoundsÂ
 SC-XRD data of compounds 4 and 5 Â
 HRMS spectra of all the compounds Â
 IC50 curves of all the compoundsÂ
 Lineweaver-Burk plots of 9n, 9e, 9m and 9h Â
 Secondary plots of 9n, 9e, 9m and 9h </p
Causes of post-operative visual impairment in the 1<sup>st</sup> and 2<sup>nd</sup> or higher generation Indian migrants living in Singapore.
<p>PVAâ=âpresenting visual acuity; BCVAâ=âbest-corrected visual acuity.</p><p>âOtherâ included one individual with pterygium, one with phthisis, one with trauma and one with myopic maculopathy. The exact cause in three individuals cannot be determined.</p
Comparison of prevalence, risk factors and outcomes of cataract surgery from selected population-based studies in Asia.
<p>APEDSâ=âAndhra Pradesh Eye Disease Study; SiMESâ=âSingapore Malay Eye Study; SINDIâ=âSingapore Indian Eye Study; ACESâ=âAravind Comprehensive Eye Study; CIEMSâ=âCentral India Eye & Medical Study; BCVAâ=âbest corrected visual acuity; PCOâ=âposterior capsular opacification; CMEâ=âcystoid macular edema; AMDâ=âage-related macular degeneration; DRâ=âdiabetic retinopathy.</p><p>âââ: not reported.</p>*<p>Age-standardized to the Indian adult population from the 2010 Singapore Census.</p
Socioeconomic and systemic factors associated with post-operative visual impairment in the 1<sup>st</sup> and 2<sup>nd</sup> or higher generation Indian migrants living in Singapore.
<p>VIâ=âvisual impairment, defined as presenting visual acuity â€20/60. ORâ=âodds ratio; CIâ=âconfidence interval.</p>*<p>p<0.05.</p
Flow diagram of the measurement protocol.
<p>Flow diagram of the measurement protocol.</p
Prevalence of cataract surgery by country of birth: 1<sup>st</sup> and 2<sup>nd</sup> or higher generation Indian immigrants living in Singapore.
<p>Nâ=ânumber of individuals in the age group; CIâ=âconfidence interval.</p>*<p>Any cataract surgery was defined as lens extraction (pseudophakia or aphakia) in either or both eyes.</p>â <p>Age- and gender-adjusted to the Indian adult population from the 2010 Singapore census.</p>§<p>Bilateral cataract surgery was defined as lens extraction (pseudophakia or aphakia) in both eyes.</p