COMPOSITION OPERATOR ON BERS-TYPE SPACES

Necessary and sufficient conditions are established for a composition operator C f = fo to be bounded or compact on the Bers-type space Ha and the little Bers-type space Ha The boundedness and compactness of the composition operator C on A() are characterized, which generalize the case of C on Ha.     

The photoreactions of some aryl esters Photo-Fries rearrangement vs photodecarboxylation—substituent and solvent effects

A number of substituted phenyl acetates have been irradiated by UV light. The reactions observed are: (1) cleavage of the O-acyl bond, leading to phenols, (2) photo-Fries rearrangements, leading to toluene derivatives. Methoxy substituents at the o- and/or p-positions were found to be displaced by the acyl moiety. The decarboxylation reaction is considerably enhanced by substitution at the o- and/or m-positions. In i-propanol and in cyclohexane no (or hardly any) decarboxylation is observed. In ether, however, the decarboxylation is pronounced. All these reactions proceed from the same excited state, the first excited singlet.     

Silicon–Nitrogen Bond Formation via Heterodehydrocoupling and Catalytic N-Silylation

Silicon–nitrogen bond formation is an important subfield in main group chemistry, and catalysis is an attractive route for efficient, selective formation of these bonds. Indeed, heterodehydrocoupling and N-silylation offer facile methods for the synthesis of small molecules through the coupling of primary, secondary, and tertiary silanes with N-containing substrates such as amines, carbazoles, indoles, and pyrroles. However, the reactivity of these catalytic systems is far from uniform, and critical issues are often encountered with product selectivity, conversions, substrate scope, catalyst activation, and in some instances, competing side reactions. Herein, a catalogue of catalysts and their reactivity for Si−N heterodehydrocoupling and N-silylation are reported.     

Teleportation via decay

We present a rare example of a decay mechanism playing a constructive role in quantum information processing. We show how the state of an atom trapped in a cavity can be teleported to a second atom trapped in a distant cavity by the joint detection of photon leakage from the cavities. The scheme, which is probabilistic, requires only a single three level atom in a cavity. We also show how this scheme can be modified to a teleportation with insurance.     

FT-IR study of the effect of zinc exposure on the biochemical contents of the muscle of Labeo rohita

Heavy metal pollution is a major environmental problem in the modern world due to increasing human activities. Zinc is an essential element involved in a wide variety of cellular processes. However, it becomes toxic when elevated concentrations are introduced into the environment. The goal of the present study is to investigate the effect of zinc exposure on the biochemical contents of the muscle tissues of freshwater species Labeo rohita using Fourier transform infrared (FT-IR) spectroscopy. Since the muscle constitutes the greatest mass of the fish that is consumed, the present study has paid particular attention to muscle component. The result reveals that the zinc exposure causes significant changes in the biochemical contents of the L. rohita muscle tissues. In addition, it causes an alteration in the protein secondary structures by decreasing the α-helix and increasing the β-sheet contents of muscle tissues. Further, it has been observed that the administration of chelating agent D-penicillamine improves the protein and lipid contents in the muscle tissues compared to zinc exposed tissues. This result shows that D-penicillamine is the effective chelator of zinc in reducing the body burden of L. rohita fingerlings.     

Simultaneous speciation of arsenic,selenium, and chromium: species stability,sample preservation,and analysis of ash and soil leachates

An analytical method using high-performance liquid chromatography separation with inductively coupled plasma mass spectrometry (ICP-MS) detection previously developed for the determination of Cr(III) and Cr(VI) has been adapted to allow the determination of As(III), As(V), Se(IV), Se(VI), Cr(III), and Cr(VI) under the same chromatographic conditions. Using this method, all six inorganic species can be determined in less than 3 min. A dynamic reaction cell (DRC)–ICP-MS system was used to detect the species eluted from the chromatographic column in order to reduce interferences. A variety of reaction cell gases and conditions may be utilized with the DRC–ICP-MS, and final selection of conditions is determined by data quality objectives. Results indicated all starting standards, reagents, and sample vials should be thoroughly tested for contamination. Tests on species stability indicated that refrigeration at 10 °C was preferential to freezing for most species, particularly when all species were present, and that sample solutions and extracts should be analyzed as soon as possible to eliminate species instability and interconversion effects. A variety of environmental and geological samples, including waters and deionized water [leachates] and simulated biological leachates from soils and wildfire ashes have been analyzed using this method. Analytical spikes performed on each sample were used to evaluate data quality. Speciation analyses were conducted on deionized water leachates and simulated lung fluid leachates of ash and soils impacted by wildfires. These results show that, for leachates containing high levels of total Cr, the majority of the chromium was present in the hexavalent Cr(VI) form. In general, total and hexavalent chromium levels for samples taken from burned residential areas were higher than those obtained from non-residential forested areas. Arsenic, when found, was generally in the more oxidized As(V) form. Selenium (IV) and (VI) were present, but typically at low levels.     

A generalized expression for the similarity of spectra: application to powder diffraction pattern classification

A generalized expression is given for the similarity of spectra, based on the normalized integral of a weighted crosscorrelation function. It is shown that various similarity and dissimilarity criteria previously described in literature can be written as special cases of this general expression. A new similarity criterion, based on this generalized expression, is introduced. The benefits of this criterion are that it properly recognizes shifted but otherwise similar details in spectra and that the resulting similarity measure is normalized. Moreover, the criterion can easily be adapted to specific properties of spectra resulting from various analytical methods. The new criterion is applied to the classification of a series of crystal structures of cephalosporin complexes, based on comparison of their calculated powder diffraction patterns. The results are compared with those obtained using previously described criteria. © 2001 John Wiley & Sons, Inc. J Comput Chem 22: 273–289, 2001     

Facile synthesis of a flexible tethered porphyrin dimer that preferentially complexes fullerene C70

A simple, high yield, two-step synthesis yields a porphyrin dimer linked by a flexible dithiol tether that preferentially binds fullerene C(70) over C(60) in toluene solution. The complex forms stable aggregates when cast on glass.     

The effect of titanium dioxide exposure on the thermal properties of Zebrafish (<Emphasis Type="Italic">Danio rerio</Emphasis>) bones

This article presents the changes in the thermal properties of the control and titanium dioxide (TiO₂), both nano and bulk exposed Zebrafish bones by using thermo analytical techniques. The result shows that the mass loss due to the thermal decomposition occurs in three distinct steps due to loss of water, organic and inorganic materials. The titanium dioxide exposed bones present a different thermal behaviour compared to the control bones. The residue masses are found to be increased due to titanium dioxide exposure. In particular, nano titanium dioxide exposure increases the residue mass level significantly (three fold) when compared to titanium dioxide bulk exposure. These thermal characteristics can be used as a qualitative method to check the metal oxide intoxication in biological samples.