Investigation of sol-gel matrices containing crude metallothionein from <Emphasis Type="Italic">Scchizosaccharomyces pombe</Emphasis> for water treatment applications

The application of silica sol–gel particles containing crude metallothionein (MT) was investigated for cadmium removal from water. The metallothionein was first extracted from the yeast Scchizosaccharomyces pombe, and entrapped in the sol–gel matrices. Then sol–gel particles with the different sizes (ranging from 45 to 225 μm) were made. The effect of different flow rates as well as different particle sizes on adsorption of cadmium was investigated. The particle size has a greater effect on Cd adsorption than flow rate in the system studied. The breakthrough curves in the column were modeled using an empirical two parameter fixed-bed adsorption model. The model relates the changes of cadmium concentration in effluent to the standard deviation (σ) and characteristic of time (t ₀).     

Design and synthesis of 2,4-dioxochroman-pyridinium-phenylacetamide derivatives as new anti-Alzheimer agents: in vitro and in silico studies

2,4-Dioxochroman-pyridinium-phenylacetamide derivatives 7a–n were synthesized and evaluated for their in vitro cholinesterase (ChE) inhibitory activities against acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE). Obtained results demonstrated that, among the synthesized compounds, two compounds, 7j and 7k , were more potent than the standard drug donepezil against BuChE and did not show cytotoxicity and carcinogenicity. Furthermore, through molecular modeling and molecular dynamic studies. we showed that these compounds can be located deep in the gorge cavity of BuChE and that they interacted with catalytic residues, acyl, and cholin-binding pockets of this enzyme. Support information     

Emission Turn‐On and Solubility Turn‐Off in Conjugated Polymers: One‐ and Two‐Photon‐Induced Removal of Fluorescence‐Quenching Solubilizing Groups

The synthesis of highly efficient two‐photon uncaging groups and their potential use in functional conjugated polymers for post‐polymerization modification are reported. Careful structural design of the employed nitrophenethyl caging groups allows to efficiently induce bond scission by a two‐photon process through a combination of exceptionally high two‐photon absorption cross‐sections and high reaction quantum yields. Furthermore, π‐conjugated polyfluorenes are functionalized with these photocleavable side groups and it is possible to alter their emission properties and solubility behavior by simple light irradiation. Cleavage of side groups leads to a turn‐on of the fluorescence while solubility of the π‐conjugated materials is drastically reduced.

     

Creation of cluster state of four ions in ion-trap system by individual addressing

The cluster state is a special, highly entangled quantum state that forms the universal resource, on which measurement-based quantum computation can be performed. In this study, a new scheme is presented for creating four-ions cluster state in ion-trap system. This scheme is based on resonant sideband excitation in which the population is transferred to target states by precise control of pulse area. Meanwhile, the scheme is consist of combination of elementary stages belonging to a universal set whereby cluster state has been created in five interaction stages by individually addressed ions with red- or blue-sideband resonance laser pulses. The paper studies the population transfer of the system by numerical solutions of the master equation, considering the effect of decoherence channels due to dissipation in the phonon modes. The presented scheme does not require control of the turn-off ratio and time delay among pulses.     

Analysis of high temperature ammonia spectra from 780 to 2100 cm

A recently-recorded set [Hargreaves et al., Astrophys. J., in press] of Fourier transform emission spectra of hot ammonia is analyzed using a variational line list. Approximately 3350 lines are newly assigned to mainly hot bands from vibrational states as high as v₂ = 2. 431 new energy levels of these states are experimentally determined, considerably extending the range of known rotationally-excited states. Comparisons with a recent study of high J levels in the ground and first vibrational states [Yu et al., J. Chem. Phys., 133 (2010) 174317] suggests that while the line assignments presented in that work are correct, their energy level predictions suffer from problems associated with the use of very high-order perturbation series in the effective Hamiltonian. It is suggested that variational calculations provide a more stable method for analyzing spectra involving highly-excited states of ammonia.     

Optimized semiempirical potential energy surface for H<Subscript>2</Subscript><Superscript>16</Superscript>O up to 26000 cm<Superscript>−1</Superscript>

A semiempirical potential energy surface is obtained for the major isotopologue of the water molecule H₂ ¹⁶O that allows the vibration-rotation energy levels in the range of 0–26000 cm⁻¹ to be calculated with an accuracy almost equal to the average experimental accuracy of measurements in the infrared and visible ranges. Variational calculations using this potential energy surface reproduce the experimental energy values of more than 1500 vibration-rotation levels of H₂ ¹⁶O with the total angular momentum quantum number J = 0, 2, and 5 in the indicated range with a standard deviation of 0.022 cm⁻¹. The potential was obtained by optimizing a starting ab initio surface using a combination of two approaches, i.e., (1) the multiplication of the starting ab initio surface by a morphing function whose parameters were optimized and (2) the optimization of parameters of the ab initio surface using both the experimental values of energy levels and the results of quantum-chemical electronic structure calculations.     

Synthesis of Novel Asymmetrical 1,4‐Dihydropyridine Derivatives

Asymmetrical 1,4‐dihydropyridine esters 3a and 3i–k were synthesized from the symmetrical precursor 1 through the intermediate 2‐bromomethyl derivative 2. Then, compound 3a was subjected to a different transformation for preparation of 1,4‐dihydropyridine derivatives 3b–h.     

Quantum Chemical Study of the Enzymatic Repair of T(6‐4)C/C(6‐4)T UV‐Photolesions by DNA Photolyases

Several strategies have evolved to repair one of the abundant UV radiation‐induced damages caused to DNA, namely the mutagenic pyrimidine (6‐4) pyrimidone photolesions. DNA (6‐4)‐photolyases are enzymes repairing these lesions by a photoinitiated electron transfer. An important aspect of a possible repair mechanism is its generality and transferability to different (6‐4) lesions. Therefore, previously suggested mechanisms for the repair of the T(6‐4)T lesion are here transferred to the T(6‐4)C and C(6‐4)T lesions and investigated theoretically using quantum chemical methods. Despite the different functional groups of the pyrimidine bases involved, a general valid molecular mechanism was identified, in which the initial step is an electron transfer coupled to a proton transfer from the protonated HIS365 to the N3^′ nitrogen of the 3^′ pyrimidine, followed by an intramolecular OH/NH₂ transfer in one concerted step, which does not require an oxetane/azetidine or isolated water/ammonia intermediate.     

Investigation of the catalytic activity of a Pd/biphenyl-based phosphine system in the Ullmann homocoupling of aryl bromides

We described Ullmann homocoupling promoted by a Pd/biphenyl-based phosphine system using DMF as solvent. Using Hammett equation it is found that the rate determining step of the reaction depends on the electronic nature of substituents of aryl bromides. Increase the rate of reaction with decreasing the electron donating of the substituent from NH₂ to H suggesting an oxidative addition step as the rate determining step. Decrease the rate of reaction with increasing the electron-withdrawing ability of the substituent from H to NO₂ indicating a reductive elimination step as the rate determining step.