[H_2N(C_2H_4)_2NH_2]_4(H_3O)[PMo_2~VMo_6~(VI)V_4~(IV)O_(40)(V~(IV)O)_2]·H_2O: A New Highly Reduced, Bicapped Pseudo-Keggin Vanadylpolymolybdophosphate

Ｐｏｌｙｏｘｏｍｅｔａｌａｔｅｓ (ＰＯＭｓ)ｃｏｎｔａｉｎｉｎｇＫｅｇｇｉｎｍｏｉ ｅｔｉｅｓｈａｖｅｂｅｅｎｒｅｃｅｉｖｉｎｇｅｘｔｅｎｓｉｖｅａｔｔｅｎｔｉｏｎｉｎｒｅｃｅｎｔｙｅａｒｓｏｗｉｎｇｔｏｔｈｅｉｒｇｒｅａｔｆｕｎｄａｍｅｎｔａｌａｎｄｐｒａｃｔｉｃａｌｉｎｔｅｒ ｅｓｔ .1Ｅｓｐｅｃｉａｌｌｙｔｈｅｕｎｕｓｕａｌｅｌｅｃｔｒｏｎｉｃｐｒｏｐｅｒｔｙ (ｈｉｇｈｎｅｇａｔｉｖｅｃｈａｒｇｅｓ) ,ｏｎｅｏｆｔｈｅｍｏｓｔｉｍｐｏｒｔａｎｔｐｒｏｐｅｒｔｉｅｓｏｆＰＯＭｓ ,ｈａｓｐｏｔｅｎ…     

GLOBAL ANALYSIS OF THE TIME-RESOL VED FLUORESCENCE OF α-CHYMOTRYPSINOGEN A AND α-CHYMOTRYPSIN POWDERS AS A FUNCTION OF HYDRATION

The time-resolved tryptophyl fluorescence of alpha-chymotrypsin A and alpha-chymotrypsin in the crystalline state and in buffer solution at room temperature was analyzed globally. Triple-exponential decay functions are necessary to adequately describe the tryptophyl fluorescence decay surfaces of the protein powders as a function of hydration and in solution. The fluorescence lifetimes of alpha-chymotrypsinogen A (tau 1 = 0.32, tau 2 = 1.30 ns, tau 3 = 3.98 ns) and alpha-chymotrypsin(tau 1 = 0.66 n s, tau 2 = 2.26 ns, tau 3 = 5.40 ns) are constant over the entire hydration range. The spectral positions of the decay-associated spectra of the hydrated powders do not shift as a function of hydration. This indicates that the structures of the zymogen and the active enzyme are unaffected by hydration. The lifetimes of alpha-chymotrypsinogen A in phosphate buffer pH 7.4 are tau 1 = 0.37 ns, tau 2 = 1.17 ns and tau 3 = 3.44 ns while the respective values of alpha-chymotrypsin are tau 1 = 0.47 ns, tau 2 = 1.40 and tau 1 = 3.89 ns.     

b 1Σ+ emissions from group V-VII diatomic molecules: bo+ → X10+, X21 emissions of SbBr

Chemiluminescence studies of the reactions of microwave-discharged oxygen with SbBr₃ have led to the observation of some band sequences in the near infrared region which are attributed to b0⁺ → X₁0⁺ and b0⁺ → X₂1 transitions of SbBr. Analysis of the spectra yielded T_e values for the X₂1 and b0⁺ states of 874 ± 10 and 12756 ± 10 cm^?1, respectively, and vibrational frequencies in the X₁0⁺, X₂1 and b0⁺ states of ω′'_e(X₁, X₂) = 257 ± 10 and ω′_e(b) = 270 ± 10cm^?1.     

Roughening of gold atomic steps induced by interaction with tetrahydrofuran

Exposure of a clean gold surface to tetrahydrofuran (THF) under ambient conditions was observed to cause roughening of atomic step edges. This change was followed in situ using a scanning tunneling microscope during the exposure of a gold surface to a controlled stream of THF vapor. THF is a common solvent used in depositing molecules, self-assembled monolayers, and polymer films on surfaces, in electrochemistry, and in chemical reactions. Unlike other solvents, such as methanol, ethanol and diethyl ether, however, we found that THF itself has a profound effect on the surface morphology that needs to be taken into account when reporting on the interactions of solutes with a gold surface. At the same time, this finding may present new opportunities in catalysis or nanostructuring of surfaces.     

Generic theory of active polar gels: a paradigm for cytoskeletal dynamics

We develop a general theory for active viscoelastic materials made of polar filaments. This theory is motivated by the dynamics of the cytoskeleton. The continuous consumption of a fuel leads to a non equilibrium state characterized by the generation of flows and stresses. Our theory can be applied to experiments in which cytoskeletal patterns are set in motion by active processes such as those which are at work in cells.     

Resonant modes in monolithic nitride pillar microcavities

GaN-based airpost pillar microcavities are realized by focused-ion beam etching starting from an all-epitaxially grown vertical-cavity surface-emitting laser structure. Pillar diameters below 1 μm are well controllable. The sidewalls are smooth and show a damaged surface layer of a thickness less than 2 nm only. Micro-photoluminescence measurements reveal the longitudinal and transversal mode spectra of the cavities in good agreement with theoretical calculations based on a vectorial transfer-matrix method.     

Comparison of tungsten and gold radiation from beam-foil excitation and tokamak-produced plasmas

Spectra in the 30–80 Å wavelength region of tungsten and gold ions, with charge states ranging from 20–33, and 25–38, respectively, have been measured in beam-foil excitation and compared with similar spectra from tokamak-produced plasmas.