Deracemization in a Complex Quaternary System with a Second-Order Asymmetric Transformation by Using Phase Diagram Studies

A productive deracemization process based on a quaternary phase diagram study of a naphthamide derivative is reported. New racemic compounds of an atropisomeric naphthamide derivative have been discovered, and a quaternary phase diagram has been constructed that indicated that four solids are stable in a methanol/H₂O solution. Based on the results of a heterogeneous equilibria study showing the stable domain of the conglomerate, a second-order asymmetric transformation was achieved with up to 97 % ee. Furthermore, this methodology showcases the chiral separation of a stable racemic compound forming system and does not suffer from any of the typical limitations of deracemization, although application is still limited to conglomerate-forming systems. We anticipate that this present study will serve as a fundamental model for the design of sophisticated chiral separation processes.     

Study of the conductivity of solid polymeric electrolyte based on PVA/GA blend with addition of acetic acid

Journal of Solid State Electrochemistry - This study searches the ion transport behavior and structural investigation of solid polymer electrolytes (SPEs) containing poly(vinyl alcohol) (PVA) and...     

Extraction of lipids from microalgae by ultrasound application: Prospection of the optimal extraction method

Microalgae have the ability to grow rapidly, synthesize and accumulate large amounts (approximately 20–50% of dry weight) of lipids. A successful and economically viable algae based oil industry will depend on the selection of appropriate microalgal strains and the selection of the most suitable lipid extraction method. In this paper, five extraction methods were evaluated regarding the extraction of lipids from Chlorella vulgaris: Bligh and Dyer, Chen, Folch, Hara and Radin, and Soxhlet. Furthermore, the addition of silica powder was studied to evaluate the introduction of more shear stress to the system as to increase the disruption of cell walls. Among the studied methods, the Bligh and Dyer method assisted by ultrasound resulted in the highest extraction of oil from C. vulgaris (52.5% w/w). Addition of powder silica did not improve the extraction of oil.     

First dinuclear Re/Tc complex as a potential bimodal Optical/SPECT molecular imaging agent

In this communication, a novel synthetic pathway has been applied to prepare a dual imaging agent in a single molecule. The dinuclear Re(I)/Tc(I) complex 6, namely [Re(CO)(3)(bipy){(4-PyrIDA)Tc(CO)(3)}], is the first example of a Re/Tc-based heterometallic assembly which could act as a potential bimodal Optical/SPECT probe. Interestingly, the Re(I) complex intermediate 4 exhibits significant photophysical properties for biological applications.     

Optimal boundary holes for the Sobolev trace constant

In this paper we study the problem of minimizing the Sobolev trace Rayleigh quotient among functions that vanish in a set contained on the boundary ∂Ω of given boundary measure.We prove existence of extremals for this problem, and analyze some particular cases where information about the location of the optimal boundary set can be given. Moreover, we further study the shape derivative of the Sobolev trace constant under regular perturbations of the boundary set.