Enantioselective Alkylation of N‐Arylhydrazones Derived from α‐Keto Esters and Isatin Derivatives through Asymmetric Phase‐Transfer Catalysis

The phase‐transfer‐catalyzed asymmetric alkylation reactions of N‐arylhydrazones derived from α‐keto‐esters and isatin derivatives afford enantioenriched azo compounds that bear a tetra‐substituted carbon stereocenter in good yields with high chemo‐ and enantioselectivity. The alkylation products can be readily converted into chiral amino esters, hydrazine derivatives, and aza‐β‐lactams without loss of enantiopurity.     

ICP-AES analysis of impurities in PuO2 after separation of Pu by TOPO impregnated XAD-4

Nuclear fuels should meet some specified characteristics to achieve their better performance in the reactor. Hence controlling and monitoring of trace level elements in the fuel materials are essential. Atomic emission spectroscopic methods are most popular for the trace level analysis. An ICP-AES procedure is described here for the trace level impurity analysis of PuO₂ produced through PUREX process. To avoid the Pu interference in the impurity analysis, initially the Pu was separated by extraction chromatography using TOPO impregnated XAD-4 resin. Magnitude of Pu interference in the impurities spectra lines was investigated. Moreover the recovery of impurity elements using the resin was established.     

Expeditious Pechmann Condensation by Using Biodegradable Cellulose Sulfuric Acid as a Solid Acid Catalyst

A facile synthesis of coumarins was performed in excellent yields via Pechmann condensation by using different type of phenols and ethylacetoacetates under solvent–free media using both conventional method and microwave irradiation in short reaction times is described. The reaction workup is very simple, and the catalyst can be easily separated from the reaction mixture and reused several times in subsequent reactions.     

Biosourced Antioxidants for Chemical Durability Enhancement of Perfluorosulfonic Acid Membrane

The chemical durability of perfluorosulfonic acid (PFSA) membranes is a topic of growing interest to meet Department of Energy (DOE) durability targets for heavy-duty vehicle (HDV) applications. State-of-the-art membranes like Nafion, rely on the use of cerium, heteropolyacids, and other inorganic additives to increase PFSA chemical durability. A less explored avenue for the oxidative stabilization of PFSA and hydrocarbon membranes is the use of organic antioxidants. No reversible organic antioxidant has been demonstrated to date which can enhance membrane lifetime by factors comparable to cerium. Here, ellagic acid (EA) is demonstrated as a promising radical scavenger for PFSA's. It is found that the incorporation of EA enhances the chemical durability of Nafion by 160%. EA, when incorporated with cerium as an electron donorenhances Nafion durability by at least 80% compared to a membrane incorporated with just cerium in DOE-defined durability tests. EA is found to be reversible in acidic conditions like those of fuel cells and its reversibility could be further enhanced by the use of suitable co-antioxidants.     

Expression of Chirality by Achiral Coadsorbed Molecules in Chiral Monolayers Observed by STM

The supramolecular packing mode of physisorbed monolayers built up by chiral isophthalic acid derivatives and coadsorbed achiral solvent molecules was imaged at the liquid/graphite interface with scanning tunneling microscopy (STM). The picture on the right shows the submolecularly resolved STM image of an enantiomorphous domain composed of the R enantiomer of the isophthalic acid derivative studied and 1-heptanol molecules; the latter express the chirality of the monolayer. Upon adsorption a racemic mixture is separated into enantiomorphous domains.     

Development of an integrated hardware and software platform for the rapid detection of cerebral aneurysm rupture

A cerebral aneurysm is defined as a weakened portion of an artery in the brain. Rupture of a cerebral aneurysm leads to subarachnoid hemorrhage (SAH). A significant number of patients with SAH are initially misdiagnosed and subjected to the risks associated with aneurysm re-rupture. Traditional detection methods recommended by physicians include computed tomography (CT) scan, lumbar puncture and angiography. Unfortunately, the CT scan is ineffective after 12 h, and angiography is best suited for those cases of finding the aneurysm before surgery. Physicians may therefore rely on lumbar puncture to develop a quick and objective evaluation by assessing xanthochromia. Bilirubin in the cerebrospinal fluid, resulting from the chemical decomposition of whole blood, is an indicator of hemorrhage. This metabolite can be detected after lumbar puncture, by differentiating its optical signature in the spinal fluid. In cases of traumatic spinal tap, bilirubin needs to be distinguished from whole blood. We introduce a diagnostic system based on visible spectroscopy to quickly and objectively assess low blood-volume SAH. The system integrates innovative hardware and a powerful software interface. We explore an algorithm that accounts for the noise and distortion from blood in the cerebrospinal fluid. We introduce a portable, user-friendly hardware platform composed of specific components designed for their sensitivity and specificity.     

Minimum component SRCO and VFO using a single DVCCC

Two oscillator topologies each employing a single differential voltage complementary current conveyor (DVCCC) are presented. The first oscillator uses a single active element, five passive components, grounded capacitors, has independent control of frequency and condition of oscillation. It has a current mode output and can be extended to provide a voltage mode output. It combines all the features of the current state-of-art oscillators. The second oscillator uses a single DVCCC, four passive elements, grounded capacitors and provides independent control of frequency. This oscillator not only has all the desired oscillator features, but requires lesser passive components. Theoretical analysis of these oscillators was verified with SPICE simulations.     

Analysis of Finasteride in Pharmaceutical Preparations by High Performance Thin Layer Chromatography

JPC – Journal of Planar Chromatography – Modern TLC - A new simple, precise, rapid, and selective high-performance thinlayer chromatography (HPTLC) method has been developed for the...     

Boolean Functions, Projection Operators, and Quantum Error Correcting Codes

This paper describes a fundamental correspondence between Boolean functions and projection operators in Hilbert space. The correspondence is widely applicable, and it is used in this paper to provide a common mathematical framework for the design of both additive and nonadditive quantum error correcting codes. The new framework leads to the construction of a variety of codes including an infinite class of codes that extend the original ((5, 6, 2)) code found by Rains It also extends to operator quantum error correcting codes.