Isomerization Mechanism in Hydrazone-Based Rotary Switches: Lateral Shift, Rotation, or Tautomerization?

Two intramolecularly hydrogen-bonded arylhydrazone (aryl = phenyl or naphthyl) molecular switches have been synthesized, and their full and reversible switching between the E and Z configurations have been demonstrated. These chemically controlled configurational rotary switches exist primarily as the E isomer at equilibrium and can be switched to the protonated Z configuration (Z-H^+) by the addition of trifluoroacetic acid. The protonation of the pyridine moiety in the switch induces a rotation around the hydrazone C═N double bond, leading to isomerization. Treating Z-H^+ with base (K_(2)CO_3) yields a mixture of E and “metastable” Z isomers. The latter thermally equilibrates to reinstate the initial isomer ratio. The rate of the Z → E isomerization process showed small changes as a function of solvent polarity, indicating that the isomerization might be going through the inversion mechanism (nonpolar transition state). However, the plot of the logarithm of the rate constant k vs the Dimroth parameter (E_T) gave a linear fit, demonstrating the involvement of a polar transition state (rotation mechanism). These two seemingly contradicting kinetic data were not enough to determine whether the isomerization mechanism goes through the rotation or inversion pathways. The highly negative entropy values obtained for both the forward (E → Z-H^+) and backward (Z → E) processes strongly suggest that the isomerization involves a polarized transition state that is highly organized (possibly involving a high degree of solvent organization), and hence it proceeds via a rotation mechanism as opposed to inversion. Computations of the Z ↔ E isomerization using density functional theory (DFT) at the M06/cc-pVTZ level and natural bond orbital (NBO) wave function analyses have shown that the favorable isomerization mechanism in these hydrogen-bonded systems is hydrazone–azo tautomerization followed by rotation around a C–N single bond, as opposed to the more common rotation mechanism around the C═N double bond

Evaluation of Compliance of Marine Fisheries of Kerala with Article 8 of FAO CCRF

It is necessary to evaluate the compliance of local fisheries with relevant provisions of the FAO Code of Conduct for Responsible Fisheries (CCRF) which is an indication of how far the code has been implemented. The present study focused on applications of the Code at the grassroot level by local fisheries m anagement authorities in marine fisheries of Kerala with reference to guidelines for fishing operations (Article 8 of FAO CCRF). A question- naire-based approach was used to demonstrate the compliance with the same. Study on marine fisheries of Kerala showed compliance on many areas of Article 8 like documentation of catch and effort, registration and licensing of fishing vessels, safety of fishers and insurance coverage. However, mesh size regulations as per section 4 of Kerala Marine Fisheries Regulation Act (KMFRA), 1980 were not followed. Other areas where improvement is required include Monitoring, Control and Surveillance (MCS), fishing gear selectivity and energy optimization. An overall 54% score was obtained for compliance of marine fisheries of Kerala with Article 8 of the code

Variation in morphometric and meristic traits of Aspidoparia morar from Brahmaputra and Barak Rivers of Assam, India

The minor carp, Aspidoparia morar is a benthopelagic fish belonging to the sub-family Danioninae under the family Cyprinidae. It has emerged as the single most dominant species in the river Brahmaputra in Assam. In the present study, 240 specimens were collected from Guwahati and Tezpur in the Brahmaputra River and Silchar in the Barak River to investigate the morphometric and meristic variation among the populations. For this a total of 20 morphometric traits and 11 meristic traits were studied. The mean lengths for most of the morphometric traits were higher for the Barak River except eye diameter, inter orbital length and anal fin length which were significantly higher on the Brahmaputra River, while the post orbital length and pelvic fin length were found to be almost equal. The regressions of standard length with all the morphometric traits except pelvic fin length, pelvic fin base, pectoral fin length, dorsal fin length, anal fin length, pre orbital length, post orbital length, inter orbital length and eye diameter showed significant variation between the rivers. Two meristic traits viz. branched rays in anal fin and gill rakers on the first gill arch also showed significant variation in the samples of the rivers

Performance Analysis and Visualization

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Visualizing network traffic to understand the performance of massively parallel simulations

pre-printThe performance of massively parallel applications is often heavily impacted by the cost of communication among compute nodes. However, determining how to best use the network is a formidable task, made challenging by the ever increasing size and complexity of modern supercomputers. This paper applies visualization techniques to aid parallel application developers in understanding the network activity by enabling a detailed exploration of the flow of packets through the hardware interconnect. In order to visualize this large and complex data, we employ two linked views of the hardware network. The first is a 2D view, that represents the network structure as one of several simplified planar projections. This view is designed to allow a user to easily identify trends and patterns in the network traffic. The second is a 3D view that augments the 2D view by preserving the physical network topology and providing a context that is familiar to the application developers. Using the massively parallel multi-physics code pF3D as a case study, we demonstrate that our tool provides valuable insight that we use to explain and optimize pF3D's performance on an IBM Blue Gene/P system

Growth Characteristics of Commonly Occurring Fresh Water Chlorophycean Algae for Biodiesel Production.

Liquid biofuels, renewable fuels derived from biomass, are arguably one of the best transition fuels for the near-term and have made a recent resurgence in response to rising oil prices. Biodiesel can be produced from a variety of lipid feedstock, catalysts and alcohols using several possible conversion processes. Microalgae reproduce themselves using photosynthesis to convert sun energy into chemical energy, completing an entire growth cycle every few days. Fresh water chlorophycean algae have great source of lipid content and proving raw material for biodiesel.  This paper focuses the growth behavior of fresh water Chlorophycean algae during mass culture for biodiesel production.&nbsp

One Step Towards Green and Sustainable Chemistry: Replacing Harsh and Corrosive Acids in Organic Chemistry Teaching Laboratories

Dr. Shainaz Landge, Assistant Professor and Dr. Abid Shaikh, Associate Professor, Department of Chemistry ($10,023.00) Replaced toxic and corrosive acids such as hydrochloric and sulfuric acids from organic chemistry teaching laboratories with greener alternatives

Legacy of Labour: The Impact of Parental Occupations on Children’s Careers Choices and Income Inequality

This paper investigates how intergenerational occupational mobility and self-selection into occupations are influenced by the occupations of parents. The results demonstrate that children who pursue their parents’ occupations, particularly those in the lowest earnings percentiles, are more negatively self-selected compared to those whose parents are in the highest earning deciles. In particular, 65% of the children who pursue their parents’ occupation in Decile 1, 49% in Decile 2, 32% in Decile 3 and 26% in Decile 4 would have achieved higher productivity and earned higher earnings in high-income occupations (specifically in Decile 10 occupations). In contrast, children from high-income backgrounds (Decile 9,10) would not have been more productive and earned more in low-income occupations, indicating a relatively efficient allocation of talent within high-income families. This suggests that negative self-selection in occupational choice is more prevalent among middle- and low-income children. These findings underscore the significant impact of occupational inheritance in perpetuating income inequality and highlight the influence of parental background on shaping an individual’s potential within specific job markets