A proton magnetic resonance study of the conformation of the seven-membered ring in benzocycloheptene

The computer analysis of the PMR spectra of several partially deuterated benzocycloheptene derivatives at ?120° provides values for all the coupling constants about the C₃? C₄ bond. An interpretaion using the Karplus equation shows unambiguously that the seven-membered ring exists as a chair conformation. The relationship between the coupling constants determined shows that the form of the Karplus equation established empirically for cyclohexane is applicable to this seven-membered ring. A comparison of coupling constants shows that the benzocycloheptene chair is more puckered than the cyclohexane chair.     

RP-HPLC prefractionation and its application in expressional proteomics analysis of an in vitro viral infection model

Prefractionation of complex protein mixtures is an efficient method for increasing the separation power of 2-DE. RP-HPLC has been successfully utilized as a prefractionation method prior to 2-DE. Here we describe the optimization of an efficient RP-HPLC method for prefractionation of baby hamster kidney cell solubilized proteins. A step gradient elution of acetonitrile was optimized and collected fractions were further examined by SDS-PAGE and 2-DE. By utilizing this method an effective increase in separation power of 2-DE is accomplished. Moreover, we describe the application of this method to expressional proteome analysis of a virally infected cell model.     

Curvature condensation and bifurcation in an elastic shell

We study the formation and evolution of localized geometrical defects in an indented cylindrical elastic shell using a combination of experiment and numerical simulation. We find that as a symmetric localized indentation on a semicylindrical shell increases, there is a transition from a global mode of deformation to a localized one which leads to the condensation of curvature along a symmetric parabolic defect. This process introduces a soft mode in the system, converting a load-bearing structure into a hinged, kinematic mechanism. Further indentation leads to twinning wherein the parabolic defect bifurcates into two defects that move apart on either side of the line of symmetry. A qualitative theory captures the main features of the phenomena but leads to further questions about the mechanism of defect nucleation.     

Natural Products in Mitigation of Bisphenol A Toxicity: Future Therapeutic Use

Bisphenol A (BPA) is a ubiquitous environmental toxin with deleterious endocrine-disrupting effects. It is widely used in producing epoxy resins, polycarbonate plastics, and polyvinyl chloride plastics. Human beings are regularly exposed to BPA through inhalation, ingestion, and topical absorption routes. The prevalence of BPA exposure has considerably increased over the past decades. Previous research studies have found a plethora of evidence of BPA’s harmful effects. Interestingly, even at a lower concentration, this industrial product was found to be harmful at cellular and tissue levels, affecting various body functions. A noble and possible treatment could be made plausible by using natural products (NPs). In this review, we highlight existing experimental evidence of NPs against BPA exposure-induced adverse effects, which involve the body’s reproductive, neurological, hepatic, renal, cardiovascular, and endocrine systems. The review also focuses on the targeted signaling pathways of NPs involved in BPA-induced toxicity. Although potential molecular mechanisms underlying BPA-induced toxicity have been investigated, there is currently no specific targeted treatment for BPA-induced toxicity. Hence, natural products could be considered for future therapeutic use against adverse and harmful effects of BPA exposure.     

Mechanism of methanol decomposition by non-thermal plasma

In this investigation available experimental data in the literature were used to propose a reaction mechanism for the destruction of methanol using non-thermal plasma technology. In a recent study [M. Derakhshesh, J. Abedi, M. Omidyeganeh, Modeling of hazardous air pollutant removal in the pulsed corona discharge, Phys. Lett. A 373 (2009) 1051–1057.] the reactor performance equation for destruction of pollutants was developed. The order of reaction for methanol decomposition is estimated using a recently developed performance model and the available experimental data. It is found that that methanol decomposition reaction follows order one. In addition, using the experimental data available in the literature the rate constant for methanol decomposition is obtained and the overall rate was compared with our previous study.     

High-order quantum resonances observed in a periodically kicked Bose-Einstein condensate

We have observed high-order quantum resonances in a realization of the quantum delta-kicked rotor, using Bose-condensed Na atoms subjected to a pulsed standing wave of laser light. These resonances occur for pulse intervals that are rational fractions of the Talbot time, and are characterized by ballistic momentum transfer to the atoms. The condensate's narrow momentum distribution not only permits the observation of the quantum resonances at 3/4 and 1/3 of the Talbot time, but also allows us to study scaling laws for the resonance width in quasimomentum and pulse interval.