Redox Reactions at Oil-Water Interface by Particle Collision Electroanalysis

Particle Collision Electrochemistry (PCE) has gained considerable attention in heterogeneous catalysis, petroleum chemistry and pharmaceutical fields. The PCE refers to a phenomenon in which a particle strikes on an inert electrode surface as a consequence of its Brownian motion and produces a spike of current for the direct oxidation/reduction of the individual particle. This method allows us characterization of individual particles and in-situ study of electrochemical reactions coupled to the particle. Herein, emulsion droplets were studied by PCE where toluene droplets contained hydrophobic tetrachloro-1,4-benzoquinone (Q). This was investigated as a model system to study the molecular effects that arise due to hydrogen bonding reagents (oleic acid, acetic acid) inside and outside of the droplets. The emulsions were prepared by sonicating toluene-quinone solution with the water phase containing an ionic liquid to provide conductivity to the droplet. Each droplet produced a current spike while colliding with the electrode surface that was held at a potential to reduce tetrachoro-1,4-benzoquinone. In bulk acetonitrile and toluene, tetrachoro-1,4-benzoquinone undergoes a two electron reduction process to form the tetrachloro phenolate di-anion (Q2-). It was shown that the hydrogen bonding affinity of Q2- for acetic acid (pKa = 4.8) was higher than for oleic acid (pKa = 9.9) for both bulk systems (as acetic acid is stronger hydrogen bonding donor than oleic acid). However, the reversed trend was observed in emulsified toluene droplets when studied by PCE. This was attributed to the preferential partition of the carboxylic acids between the two phases in the emulsion. Oleic acid stays inside the droplets due its hydrophobic nature and hydrogen bonding with Q2- takes place inside the droplet. In contrast, solvation of acetic acid by the surrounding water, causes the hydrogen bonding with Q2- to occur significantly less inside the droplet. Another redox system studied by PCE was hydrophobic ferrocene (Fc) trapped in the toluene droplet to determine the effect of surfactant on the particle size. The diameter determined electrochemically was compared with Dynamic Light Scattering (DSL) measurements. The presence of nonionic surfactant (triton X-100) was observed to affect the droplet’s size easily monitored by PCE. The mediated oxidation of cysteine by the oxidized Fc inside the droplet was investigated at different concentrations of cysteine

Influence of Dam and Foundation Discountinuities Using Discountinuum Approach — A Case Study

Dam-foundation interaction plays an important role in the design and analysis of concrete gravity dams as has been reviewed from the failures of dams in the literature. The objective of the study is to understand the behavior of a concrete gravity dam taking into account the effect of dam and foundation discontinuities using three-dimensional Distinct Element Code. Different models have been formulated considering the complexities involved in the modeling of the dam structure, dam-foundation system and the results have been compared. Modeling the dam with the discontinuity in the form of crack which runs through the concrete section has a complex phenomenon taking place at the interface where sliding and rotation deformation contribute to the overall stability. Modeling dam with discontinuities in the dam monoliths proved to be more realistic in the analysis of dam than considering a monolith dam with no dam discontinuities. Significant relative displacements between the monoliths and the permanent relative displacement at the end of seismic input have been observed at the discontinuities in this case. Modeling the foundation rock discontinuities represent the field conditions in the analysis more realistically. It is clearly indicated from the study that the interaction between dam monoliths and discontinuities in the foundation rock mass provide more realistic dam response

Efficacy of Withania somnifera on lipid profile of endosulfan induced toxicity in Swiss albino mice

India is an agrarian country with crops cultivated at a huge scale. Pesticides in recent times have caused serious health hazards in the population which are widely used by the farmers for the better yield of crops. Endosulfan is an organochlorine pesticide, which is widely used by the farmers. But, in the present times, it has caused serious health hazards in the exposed population causing various diseases, including cancer. Hence, the present study on animal aims to observe the protective effect of Withania somnifera against endosulfan induced toxicity in Swiss albino mice. Endosulfan at the dose of 3mg/Kg body weight per day was administered orally to Swiss albino mice for 4 weeks. Then after, W. somnifera at the dose of 1000 mg/Kg b.w. was orally administered for 4 weeks. Mice were sacrificed after the completion of the entire treatment. After dissection, the blood samples were collected for biochemical assay, especially for lipid profile analysis. The lipid profile study showed inclination in the Total cholesterol level (117±6.686 mg/dl), Cholesterol (LDL) (78.83±4.151mg/dl), level and Triglycerides level (60.83±2.613mg/dl), while declination in Cholesterol (HDL) (13.50±1.33mg/dl), level after Endosulfan exposure. But, upon W. somnifera treatment to the endosulfan treated group showed significant (p<0.001) normalisation in the lipid profile levels. Therefore, it was concluded that W. somnifera played a vital role to control the endosulfan induced toxicity

Protective effect of ascorbic acid against fenvalerate induced toxicity in air-breathing fish Clarias batrachus

The food demand in recent times has increased many folds. In order to augment the need for food, the agriculture practice is extensively carried out by the farmers and pesticides are widely used by them for the better yield of crops. Fishes are also cultivated by these farmers, and humans are consuming the fishes as they are very high nutritious food product. But, these pesticides through agricultural runoffs are contaminating the ponds as well the aquatic fauna like fish. The present research work deals with the evaluation of the protective effect of ascorbic acid on fenvalerate induced nephrotoxicity in Clarias batrachus. The pyrethroid pesticide- Fenvalerate EC 20% was administered directly in the water contained in the aquarium at the dose of 0.027 ppm, 0.042 ppm and 0.083 ppm respectively for 96 hrs hours after the dose calculation through LC50. Thereafter, ascorbic acid was administered orally by gastric intubation method at the dose of 200 mg/Kg body weight per day for 04 days to each pesticide treated group. The study revealed that, after the exposure of fenvalerate, there was significant damage at the biochemical levels like urea, creatinine, protein and albumin and histopathological study of kidney tissue in fish C. batrachus. But, after the administration of ascorbic acid, there was a significant restoration in the biochemical levels and in histopathology of the kidney of fish. The study concluded that Ascorbic acid possessed protective effect against fenvalerate induced toxicity in C. batrachus

The 1998 floods in Bangladesh: disaster impacts, household coping strategies, and responses

This report combines a careful analysis of government policy and private foodgrain markets with a detailed survey of 757 households in rural Bangladesh in November and December 1998, about two months after the floodwaters receded. The report describes short- and medium-term government policy measures taken to encourage private trade, including an earlier trade liberalization that permitted private-sector imports of rice from India that stabilized private markets and largely offset the decline in production. The impact of the floods on household assets, employment, consumption, and nutritional outcomes is analyzed using the micro-level survey data. The study finds that flood-exposed households were, in general, able to avoid severe declines in food consumption and nutritional status through a combination of private-sector borrowing... and targeted government and NGO transfers.Food relief Bangladesh., Food supply Bangladesh., Disasters Asia., Households Bangladesh.,

Information and Timing in Repeated Partnerships

In a repeated partnership game with imperfect monitoring, we distinguish among the effects of (1) shortening the period over which actions are held fixed, (2) increasing the frequency with which accumulated information is reported, and (3) reducing the amount of discounting of payoffs between successive periods. While reducing the amount of discounting generally improves incentives for cooperation, the other two changes can have the reverse effect. When the game is specified in the customary way with information reported at the end of each period of fixed action, the net effect of shortening the period length can be to destroy all incentives for cooperation, reversing the usual conclusion associated with the Folk Theorem for repeated games. Moreover, when interest rates are low, reducing the frequency of information reporting can greatly enhance the efficiency of equilibrium