Electrical detection of amine ligation to a metalloporphyrin via a hybrid SOI-MOSFET

A close-packed monolayer of zinc 5,10,15,20-tetrakis(3-carboxyphenyl)porphyrin has been prepared and deposited on the thin native oxide covering the surface of an SOI-MOSFET (silicon-on-insulator metal-oxide-semiconductor field effect transistor) using Langmuir-Blodgett techniques. When the device is exposed to amine vapors in a nitrogen atmosphere, the amine coordinates to the zinc atom. The resulting change in electron distribution within the porphyrin leads to a large change in the drain current of the transistor, biased via a back gate. This change is sensitive to both the amount of amine present and the base strength of the amine. Only very small changes in drain current were observed with a monolayer of free base porphyrin or palmitic acid. After exposure to high pyridine concentrations, the device response saturates, but partially recovers after overnight exposure to flowing nitrogen gas. Interestingly, the device response is instantaneously reset by exposure to visible light, suggesting that photode-ligation occurs. An electrical model for the hybrid device that describes its response to ligand binding in terms of a change in the work function of the porphyrin monolayer has been developed. A transistor response to a few hundred attomoles of bound pyridine can be readily detected. This extreme sensitivity, coupled with the ability to reset the device using light, suggests that such systems might be useful as sensors.     

Vibrational spectroscopy of resveratrol

In this article the authors deal with the experimental and theoretical interpretation of the vibrational spectra of trans-resveratrol (3,5,4'-trihydroxy-trans-stilbene) of diverse beneficial biological activity. Infrared and Raman spectra of the compound were recorded; density functional calculations were carried out resulting in the optimized geometry and several properties of the molecule. Based on the calculated force constants, a normal coordinate analysis yielded the character of the vibrational modes and the assignment of the measured spectral bands.     

Multiple beneficial effects of resveratrol and their chemical-biochemical basis

On the basis of in vitro and in vivo investigations trans-resveratrol (RV) is a natural, concentration-dependent formaldehyde (HCHO) mobilizer, scavenger, capture and carrier molecule. The capturing and mobilization of HCHO from a given biological unit (e.g. tissue) with RV (first step) generates a chemopreventive effect. The reaction products between endogenous HCHO and RV (second step) may exert killing/inhibiting effects on pathogens and/or cancer cells. These two steps result in the double effect of RV. From the model reaction mixture of RV and HCHO in diluted formalin solution, different reaction products were detected, separated and identified. Similar reactions can be observed between RV and endogenous HCHO in plant and animal tissues as well. Capturing the HCHO molecules in model experiments with HCHO-capture molecules (in vitro conditions) the antibacterial activity of RV decreased substantially. The in vitro investigations were extended to in vivo conditions. The discovery of a quadruple immune response of plants to pathogens resulting from pretreatment with RV opens new horizons in the confirmation of the diverse beneficial effects of RV.     

Overpressured layer chromatography (OPLC)--a flexible tool of analysis and isolation

This review briefly summarizes the overpressured layer chromatography (OPLC) technique and its progress from the beginning until today. Some theoretical aspects, important technical and methodological solutions, as well as analytical separations and isolations are demonstrated covering the last 30 years. The infusion and transfusion OPLC operations, as well as their combination, and their off-line and on-line processes, and off-line and on-line hyphenations for detection and structure elucidation are presented. The combination of OPLC separation with biological detection by direct bioautography and BioArena as an important solution touches the potential of analysis and isolation based on biological activity.     

The Essential Norm of Weighted Composition Operators on Weighted Banach Spaces of Analytic Functions

For a wide class of radial weights we calculate the essential norm of a weighted composition operator uC_j{uC_\varphi} on the weighted Banach spaces of analytic functions in terms of the analytic function u \colon \mathbb D ? \mathbb C{u \colon \mathbb D \to \mathbb C} and the nth power of the analytic selfmap j{\varphi} of the open unit disc \mathbb D{\mathbb D} . We also apply our result to calculate the essential norm of composition operators acting on Bloch type spaces with general radial weights.     

Lentivirus-mediated transgene delivery to the hippocampus reveals sub-field specific differences in expression

Background  

In the adult hippocampus, the granule cell layer of the dentate gyrus is a heterogeneous structure formed by neurons of different ages, morphologies and electrophysiological properties. Retroviral vectors have been extensively used to transduce cells of the granule cell layer and study their inherent properties in an intact brain environment. In addition, lentivirus-based vectors have been used to deliver transgenes to replicative and non-replicative cells as well, such as post mitotic neurons of the CNS. However, only few studies have been dedicated to address the applicability of these widespread used vectors to hippocampal cells in vivo. Therefore, the aim of this study was to extensively characterize the cell types that are effectively transduced in vivo by VSVg-pseudotyped lentivirus-based vectors in the hippocampus dentate gyrus.     

Mössbauer studies of the interaction of oxygen with solid β-Fe-phthalocyanine

Oxygen has been diffused into the interplanar spacings of solid β-Fe^IIPc at relatively low temperatures in the dry state and in aqueous suspensions. A variety of oxygen adducts are stabilized in the solid matrix, which do not exist in solution. Tentative assignment of species have been made with the help of Mössbauer and IR spectroscopy.     

Synthesis and stereochemistry of tetrahydro-4-aryl-3-[(dimethylamino)methyl]-2H-pyranols as potential analgesics

Diastereomeric cis- and trans-tetrahydro-4-aryl-3-[(dimethylamino)methyl]-2H-pyranols derived from 3-[(dimethylamino)methyl]tetrahydro-4H-pyran-4-one ( 5 ), have been prepared and their configurations were established on the basis of ir data. The biologically more potent trans isomer 3 was resolved into its optical antipodes and the absolute stereochemistry of one of the enantiomers 14 , was determined by X-ray crystallography. Some of the compounds showed analgesic activity comparable to codeine.