Ketamine exerts powerful anesthetic, psychotic and anti-depressant effects in both healthy volunteers and clinically-depressed patients. Although ketamine targets particular glutamate receptors, there is a dearth of evidence for additional, alternative molecular substrates for the behavioral actions of this NMDA receptor antagonist drug. Here, we provide behavioral and molecular evidence for the actions of ketamine using a new vertebrate model for psychiatric disorders: the zebrafish. Sub-anesthetic doses of ketamine produced a variety of abnormal behaviors in zebrafish that were qualitatively analogous to those previously measured in humans and rodents treated with drugs that produce transient psychosis. In addition, we revealed that the transcription factor Phox2b is a molecular substrate for the actions of ketamine, particularly during periods of hypoxic stress. Finally, we also show that SIRT1, a histone deacetylase widely recognized for its link to cell survival is also affected by hypoxia crises. These results establish a relevant assay system in which the effects of psychotomimetic drugs can rapidly be assessed, and provide a plausible and novel neuronal mechanism through which ketamine affects critical sensory circuits that monitor breathing behavior.

A novel series of oxy-diester-functionalized gemini surfactants (Cm-E2O-Cm) were synthesized and a comprehensive analysis of their biophysicochemical properties was carried out.

Waxy crude oil has become a crucial unconventional oil alternative owing to the depleting conventional oil resources. However, ascertaining flow assurance in a waxy crude oil pipeline at low temperatures is challenging due to the high viscosity and gelation properties of waxy crude oil and wax deposition on the pipeline wall. Researchers and industries use different classes of chemical additives to resolve the flow assurance issues. The current review aims to build a relationship between the structural properties of chemical additives and their flow improvement efficacy. A wide array of compounds reported in the past decade has been critically examined to understand the progress in the field. Polymers form a bulk of these compounds. However, there is a shift toward polymer nanocomposites owing to their better effect compared to pure polymers. Surfactants, organic solvents, and other molecules have also been utilized as additives to ensure flow during waxy crude oil transportation. The presence of different structural properties such as alkyl chain length, aromatic rings, size of aromatic rings, polar groups, and others have been related to their effect on the flowability of waxy crude oil. Moreover, the factors related to scaling of lab-scale results to industry level have been enumerated. The future directions and perspectives related to utilizing structure–efficacy relationships of chemical additives have been discussed. In contrast to the existing literature, special importance has been given to the chemical structures of additives and their molecular interactions with waxy oils. The perspective of the structure–efficacy relationship will help in designing novel additives with greater efficacy and suitability for waxy crude oil.

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In this study, we prepared a novel series of diester-functionalized cationic gemini surfactants (C m-E2O2-C m) containing ethylene oxide as a spacer with varying alkyl chain lengths and characterized by 1 H NMR, FT-IR, elemental analysis, and ESI-MS. The physicochemical properties of the geminis were explored by tensiometry, fluorescence, dye solubilization, and Krafft point. These geminis acquire superior surface activity than the conventional surfactants. Fluorescence spectroscopy analysis affirmed that the micropolarity and aggregation number of micelles diminished with increase in the alkyl chain length. These geminis represent a new group of amphiphiles of considerably high biodegradability, better cleavability, and low toxicity as assessed by BOD test, FT-IR analysis, and HC 50 analysis, respectively. They also showed significant level of antimicrobial activity toward some specified bacterial strains of Gram-positive and Gram-negative by using agar well diffusion method. Furthermore, the thermogravimetric analysis provided information regarding thermal stabilities of the newly synthesized gemini surfactants. Keywords C m-E2O2-C m gemini surfactants Á Physicochemical properties Á Antimicrobial activities Á TGA

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