Magnetoelectric Coupling through the Spin Flop Transition in Ni_{3}TeO_{6}

We combined high field optical spectroscopy and first principles calculations to analyze the electronic structure of Ni_{3}TeO_{6} across the 53 K and 9 T magnetic transitions, both of which are accompanied by large changes in electric polarization. The color properties are sensitive to magnetic order due to field-induced changes in the crystal field environment, with those around Ni1 and Ni2 most affected. These findings advance the understanding of magnetoelectric coupling in materials in which magnetic 3d centers coexist with nonmagnetic heavy chalcogenide cations.

Observations of Co4+ in a higher spin state and the increase in the Seebeck coefficient of thermoelectric Ca3Co4O9

Ca3Co4O9 has a unique structure that leads to exceptionally high thermoelectric transport. Here we report the achievement of a 27% increase in the room-temperature in-plane Seebeck coefficient of Ca3Co4O9 thin films. We combine aberration-corrected Z-contrast imaging, atomic-column resolved electron energy-loss spectroscopy, and density-functional calculations to show that the increase is caused by stacking faults with Co4+-ions in a higher spin state compared to that of bulk Ca3Co4O9. The higher Seebeck coefficient makes the Ca3Co4O9 system suitable for many high temperature waste-heat-recovery applications.

Ab-initio adsorption study of chitosan on functionalized graphene: critical role of van der Waals interactions

We investigate the adsorption process of an organic biomolecule (chitosan) on epoxy-functionalized graphene using ab-initio density functional methods incorporating van-der-waals (vdW) interactions. The role of London dispersion force on the cohesive energy and conformal preference of the molecule is quantitatively elucidated. Functionalizing graphene with epoxy leads to weak hydrogen-bond interactions with chitosan. Binding energy values increase by over an order of magnitude after including vdW corrections, implying that dispersive interactions dominate the physisorption process. Conformal study show binding upto 30 kcal/mol when the molecule is oriented with the hydroxyl group approaching the functionalized graphene. Our study advances the promise of functionalized graphene for a variety of applications.

Effect of substrate on the atomic structure and physical properties of thermoelectric Ca₃Co₄O₉ thin films

The incommensurately layered cobalt oxide Ca(3)Co(4)O(9) exhibits an unusually high Seebeck coefficient as a polycrystalline bulk material, making it ideally suited for many high temperature thermoelectric applications. In this paper, we investigate properties of Ca(3)Co(4)O(9) thin films grown on cubic perovskite SrTiO(3), LaAlO(3), and (La(0.3)Sr(0.7))(Al(0.65)Ta(0.35))O(3) substrates and on hexagonal Al(2)O(3) (sapphire) substrates using the pulsed laser deposition technique. X-ray diffraction and transmission electron microscopy analysis indicate strain-free growth of films, irrespective of the substrate. However, depending on the lattice and symmetry mismatch, defect-free growth of the hexagonal CoO(2) layer is stabilized only after a critical thickness and, in general, we observe the formation of a stable Ca(2)CoO(3) buffer layer near the substrate-film interface. Beyond this critical thickness, a large concentration of CoO(2) stacking faults is observed, possibly due to weak interlayer interaction in this layered material. We propose that these stacking faults have a significant impact on the Seebeck coefficient and we report higher values in thinner Ca(3)Co(4)O(9) films due to additional phonon scattering sites, necessary for improved thermoelectric properties.

Chromium III exposure inhibits brain Na+K+ATPase activity of Clarias batrachus L. involving lipid peroxidation and deficient mitochondrial electron transport chain activity

The present study elucidated the role of lipid peroxidation and diminished mitochondrial electron transport chain activity in partial dysfunction of brain Na+K+ATPase of Clarias batrachus exposed to chromium III ions. The fish were exposed to 10% and 20% of the derived 96 h LC50 value, 5.69 mg/L and 11.38 mg/L, respectively, and sampled on 20, 40 and 60 days. Exposure to chromium III on fish brain demonstrated an increased lipid peroxidation, production of protein carbonyl and reactive oxygen species and loss of protein thiol groups in synaptosomal fraction with decreased activity of Na+K+ATPase, partial inactivation of mitochondrial electron transport chain activity and energy depletion.

Assessment of the impact of pesticide residues on microbiological and biochemical parameters of tea garden soils in India

The main aim of this study was to assess the impact of pesticidal residues on soil microbial and biochemical parameters of the tea garden soils. The microbial biomass carbon (MBC), basal (BSR) and substrate induced respirations (SIR), beta-glucosidase activity and fluorescein diacetate hydrolyzing activity (FDHA) of six tea garden soils, along with two adjacent forest soils (control) in West Bengal, India were measured. The biomass and its activities and biochemical parameters were generally lower in the tea garden soils than the control soils. The MBC of the soils ranged from 295.5 to 767.5 micro g g(- 1). The BSR and SIR ranged from 1.65 to 3.08 mu g CO2-C g(- 1) soil h(- 1) and 3.08 to 10.76 micro g CO2-C g(- 1)h(- 1) respectively. The beta-glucosidase and FDHA of the soils varied from 33.3 and 76.3 micro g para-nitrophenol g(- 1) soil h(- 1) and 60.5 to 173.5 micro g fluorescein g(- 1)h(- 1)respectively. The tea garden soils contained variable residues of organophosphorus and organochlorine pesticides, which negatively affected the MBC, BSR, SIR, FDHA and beta -glucosidase activity. Ethion and chlorpyriphos pesticide residues in all the tea garden soils varied from 5.00 to 527.8 ppb and 17.6 to 478.1 ppb respectively. The alpha endosulfan, beta endosulfan and endosulfan sulfate pesticide residues in the tea garden soils ranged from 7.40 to 81.40 ppb, 8.50 to 256.1 ppb and 55 to 95.9 ppb respectively. Canonical correlation analysis shows that 93% of the total variation was associated with the negative impact of chlorpyriphos, beta and alpha endosulfan and endosulfan sulfate on MBC, BSR and FDHA. At the same time ethion had negative impact on SIR and beta-glucosidase. Data demonstrated that the pesticide residues had a strong impact on the microbial and biochemical components of soil quality.

Intradiploic haematoma behaving as a progressive mass lesion

A 17-year-old boy presented with a slowly growing right frontal bone swelling over an 8-year period. The swelling resulted in marked proptosis and reduced his visual acuity and eye movements. He was found to have clotting factor VIII deficiency. A chronic intradiploic haematoma as the cause of the swelling was a surprise finding.

Perception of an aggressor and his victim as a function of their relationship and retaliation

Two experiments, using a simple incident of aggression described in a passage, were conducted to study the evaluation of an aggressor (Study II) and his victim (Study I) as a function of their relationship. Both studies used a 2 (subjects' sex) × 2 (aggressor superior to victim vs aggressor subordinate to victim) × 2 (retaliating vs nonretaliating victim) factorial design, with 20 college students per cell as subjects ( N = 320). The nonretaliating victim was rated more positively than the retaliating victim on all dimensions. The aggressor tended to be more favorably judged when the victim was a superior rather than a subordinate, although this was not true of all conditions or of all dimensions.