10 research outputs found
Synthesis and characterization of iron(III) complexes of salicylaldehyde 4-methoxybenzoyl hydrazone
107-111lron(lll) complexes of salicylaldehyde 4-methoxybenzoyl hydrazone, (H2smbhon), have been isolated and the reactions of [Fe(smbhon) (Cl) (H2O)]2 with SnCl2 and CH3CN are discussed. These complexes have been characterised by elemental analyses, molar conductance values, magnetic susceptibilities, molecular weights and spectroscopic (electronic,infrared and Mössbauer) data. Depending on the reaction conditions, the ligand may function as a dibasic tridentate, monobasic or neutral bidentate ligand
Synthesis and characterization of iron(III) complexes of diacetylbis- (4-methoxybenzoyl hydrazone)
529-534A few mono- and binuclear iron(III) complexes have been isolated by the reaction of diacetylbis( 4-methoxybenzoyl hydrazone), H2dambhon with iron salts under varied reaction conditions. Some reactions of [(dambhon)Fe(Cl)(H2O)].4H2O, isolated in this study, with acetylacetone, pyridine, SnCl2 and PPh3 have been carried out which afforded new iron(III) complexes. The new complex [(dambhon)Fe(PPh3)Cl], thus prepared, smoothly reacts with thiomethanol, N-trimethylsilyldimethylamine, benzyltrimethylsilane, and p-bis(trimethylsilylmethyl)benzene leading to the isolation of several new iron(III) and organoiron(III) compounds.. The complexes are characterized on the basis of elemental analyses, molar conductance, molecular weight, magnetic susceptibilities and spectroscopic (electronic, IR and Mössbauer) data. The ligand H2 dambhon in these complexes functions as a NNOO donor either as a mono- or dianion or neutral ligand
Size-Dependent Conformational Features of Aβ<sub>17–42</sub> Protofilaments from Molecular Simulation Studies
Alzheimer’s disease is caused
due to aggregation of amyloid
beta (Aβ) peptide into soluble oligomers and insoluble fibrils
in the brain. In this study, we have performed room temperature molecular
dynamics simulations to probe the size-dependent conformational features
and thermodynamic stabilities of five Aβ<sub>17–42</sub> protofilaments, namely, O<sub>5</sub> (pentamer), O<sub>8</sub> (octamer),
O<sub>10</sub> (decamer), O<sub>12</sub> (dodecamer), and O<sub>14</sub> (tetradecamer). Analysis of the free energy profiles of the aggregates
showed that the higher order protofilaments (O<sub>10</sub>, O<sub>12</sub>, and O<sub>14</sub>) undergo conformational transitions
between two minimum energy states separated by small energy barriers,
while the smaller aggregates (O<sub>5</sub> and O<sub>8</sub>) remain
in single deep minima surrounded by high barriers. Importantly, it
is demonstrated that O<sub>10</sub> is the crossover point for which
the twisting of the protofilament is maximum, beyond which the monomers
tend to rearrange themselves in an intermediate state and eventually
transform into more stable conformations. Our results suggest that
the addition of monomers along the axis of an existing protofilament
with a critical size (O<sub>10</sub> according to the present study)
proceeds via an intermediate step with relatively less stable twisted
structure that allows the additional monomers to bind and form stable
larger protofilaments with minor rearrangements among themselves.
More importantly, it is demonstrated that a combination of twist angle
and end-to-end distance can be used as a suitable reaction coordinate
to describe the growth mechanism of Aβ protofilaments in simulation
studies
<span style="font-size:12.0pt;font-family:"Times New Roman","serif"; mso-fareast-font-family:Calibri;mso-fareast-theme-font:minor-latin;mso-ansi-language: EN-IN;mso-fareast-language:EN-US;mso-bidi-language:AR-SA">Synthesis and charaterisation of cobalt complexes of salicylaldehyde 4-methoxybenzoyl hydrazone (H<sub>2</sub> smbhon)</span>
1139-1144A
number of mononuclear and dinuclear cobalt(II) and cobalt(III) complexes have been isolated by reacting salicylaldehyde 4- methoxybenzoyl hydrazone (H2smbhon)
with CoCI2.6H2O, CO(NO3)26H2O, Co(CH3COO)2.4H2O
and Co(acac)3 under varied
reaction
conditions. [CoII(smbhon)(H2O)3], isolated
in this study,
further reacts with pyridine (Py) dipyridine (dip) and
triphenylphosphine (Ph3P) in presence of
NaCIO4 to form new cobalt(III)
complexes. Equimolar mixtures of [CoII(smbhon)(H2O)3] and the
ligands like
acetylacetone (Hacac), glycine (Hgly), N,N-bisethyleneacteophenoneimine
(bape),N-phenylsalicylaldimine (Haslan), N-phenylorthohydroxyacetophenoneimine
(Hohapan), N-hydroxymethylsalicylaldimine
(H2salgly), N-2-hydroxyphenylsalicylaldimine (H2saloap) or N-2-carboxyphenylsalicylaldimine
(H2salana)
on refluxing in methanol-acetonitrile
in the presence of oxygen at pH ~
9 afford coloured heterochelates of cobalt (III) in high yields.
Structures of the complexes have been
assigned on the basis of elemental analyses,
molecular
weights, molar conductances, magnetic moments
and spectral (UV -vis and IR) studies. The physico-chemical data suggest that H2smbhon
can behave as a dibasic
tridentate (ONO) donor, monobasic tridentate (ONO) (keto form) donor and monobasic
bidentate (NO) donor depending on the reaction conditions
Application of Oil Condition Monitoring Techniques for Improving Critical Equipment Availability in Steel Plant
The particles contained in the lubricating oil carry detailed and important information about the condition of the machine. The information may be deduced from particle shape, composition, size distribution and concentration. Particles eroded from the surface of an oil wetted component in any centralized lubrication system upon examination give specific and accurate information. The operating wear modes prevailing in the machine are determined with the examination of the lubricant in circulation. Analytical and experimental studies were undertaken to assess the deleterious effect of contaminants present in lubricant on the performance of critical equipment in steel plant. The study involves the findings of typical characteristics developed in the oil wetted components on account of contaminants. Morphology of worn out particles, change in chemistry of lubricant and the presence of contaminants in the centralized system was optimized. The experimental methods include quantification of total ferromagnetic particles through direct reading and analytical ferrography, particle size in a laser diffraction particle counter and deleterious particles present in the lubricant through an Oil View Analyser instrument and an inductive couple plasma unit. The above condition based analytical techniques were used to predict the overall health of the critical equipment located in different units of steel plant
Effects of a Solar Eclipse on the Propagation of VLF-LF Signals: Observations and Results
The results from the measurements of some of the fundamental parameters (amplitude of sferics and transmitted signal, conductivity of lower ionosphere) of the ionospheric responses to the 22 July 2009 solar eclipse (partial: 91.7%) are shown. This study summarizes our results from sferics signals at 81 kHz and subionospheric transmitted signals at 19.8 and 40 kHz recorded at Agartala, Tripura (latitude: 23¢XN, longitude: 91.4¢XE). We observed significant absorption in amplitude of these signals during the eclipse period compared to their ambient values for the same period during the adjacent 7 days. The signal strength along their propagation paths was controlled by the eclipse associated decrease in ionization in the D-region of the ionosphere. Waveguide mode theory calculations show that the elevation of the height of lower ionosphere boundary of the Earth-ionosphere waveguide to a value where the conductivity parameter was 106 unit. The absorption in 81 kHz sferics amplitude is high compared to the absorption in the amplitude of 40 kHz signal transmitted from Japan. The simultaneous changes in the amplitudes of sferics and in the amplitude of transmitted signals assert some sort of coupling between the upper atmosphere and the Earth¡¦s near-surface atmosphere prevailing clouds during solar eclipse
Not Available
Not AvailablePresent study is a maiden attempt to assess
net ecosystem exchange (NEE) of carbon dioxide
(
CO2) flux from jute crop (Corchorus olitorius L.)
in the Indo-Gangetic plain by using open-path eddy
covariance (EC) technique. Diurnal variations of NEE
were strongly influenced by growth stages of jute crop.
Daytime peak NEE varied from − 5 μmol m−
2 s−
1
(in germination stage) to − 23 μmol m−
2 s−
1 (in fibre
development stage). The ecosystem was net CO2
source during nighttime with an average NEE value
of 5–8 μmol m−
2 s−
1. Combining both daytime and
nighttime CO2
fluxes, jute ecosystem was found to be
a net CO2
sink on a daily basis except the initial 9 days
from date of sowing. Seasonal and growth stage-wise
NEEs were computed, and the seasonal total NEE over the jute season was found to be − 268.5 gC m−
2 (i.e.
10.3 t CO2
ha-
1). In different jute growth stages,
diurnal variations of NEE were strongly correlated
(R2 > 0.9) with photosynthetic photon flux density
(PPFD). Ecosystem level photosynthetic efficiency
parameters were estimated at each growth stage of
jute crop using the Michaelis–Menten equation. The
maximum values of photosynthetic capacity (Pmax,
63.3 ± 1.15 μmol CO2
m−
2 s−
1) and apparent quantum
yield (α, 0.072 ± 0.0045 μmol CO2
μmol photon−
1)
were observed during the active vegetative stage, and
the fibre development stage, respectively. Results of
the present study would significantly contribute to
understanding of the carbon flux from the Indian agroecosystems,
which otherwise are very sparse.Not Availabl