Is there an optimal topographical surface in nano-scale affecting protein adsorption and cell behaviors? Part II

Although nano-structured surfaces exhibit superior biological activities to the smooth or micro-structured surfaces, whether there is an optimal topographical surface in nano-scale affecting protein adsorption and cell behaviors is still controversial. In this study, porous aluminum oxide membranes with different pore sizes ranging from 25 to 120 nm were prepared by the anodic oxidation technique. The surface morphology, topography and wettability were analyzed by scanning electron microscope, atomic force microscope and water contact angle measurement, respectively. The results indicated that the synergistic action of the nano-topography structure and hydrophilic/hydrophobic properties resulted in a highest protein adsorption on the aluminum oxide membrane with 80 nm pore size. Additionally, the morphological, metabolic and cell counting methods showed that cells had different sensitivity to porous aluminum oxide membranes with different surface features. Furthermore, this sensitivity was cell type dependent. The optimal pore size of aluminum oxide membranes for cell growth was 80 nm for PC12 cells and 50 nm for NIH 3T3 cells.     

Effect of geometrical stress concentrators on the band formation and the serrated deformation in aluminum–magnesium alloys

The effect of holes on the band formation and the serrated deformation in planar specimens of aluminum–magnesium alloys AlMg5 and AlMg6 is studied by high-speed video filming of moving deformation bands. It is found that the concentration of an elastic field near a hole causes early nucleation of macrolocalized deformation bands and decreases the critical deformation of the first stress drop. Differences between the spatial–temporal patterns of deformation bands near holes under various deformation conditions are revealed.     

Heat transfer enhancement—a review of techniques and their possible impact on energy efficiency in the U.K.

There are many techniques for enhancing heat transfer. These may be usefully categorized as active or passive in nature. Approximately 20 enhancement methods are reviewed in this paper, and their status in the United Kingdom discussed. An attempt is made to predict the effect more widespread use of enhancement would have on energy cost savings due to heat recovery. The use of enhancement in other unit operations is briefly discussed. Recent U.S. patents on enhancement methods are reviewed.     

The effect of orientation and distance between donor and acceptor molecules on the efficiency of singlet–singlet energy transfer in Langmuir–Blodgett films

Singlet–singlet energy transfer between molecules of fluorescein and oxazine dyes in Langmuir–Blodgett films is studied experimentally. The dependence of the energy-transfer efficiency on the distance shows that the quenching of the donor fluorescence is the most efficient when the layers of the donor and acceptor molecules are in a direct contact. An increase in the distance between the donor and acceptor layers leads to a decrease in the energy-transfer efficiency. To establish the mutual orientation of the donor and acceptor molecules, quantum-chemical calculations of the energy transfer process in the donor–acceptor pair are carried out. The calculations show that the best correlation of the experimental and calculated values of the energy-transfer efficiency is observed when the interacting particles are shifted relative to each other by about ~0.12 nm in parallel planes. The presented approach can be used to estimate the relative orientation of interacting particles in multimolecular ensembles.     

Is the Kramers-Kronig relationship between ultrasonic attenuation and dispersion maintained in the presence of apparent losses due to phase cancellation?

Phase cancellation effects can compromise the integrity of ultrasonic measurements performed with phase sensitive receiving apertures. A lack of spatial coherence of the ultrasonic field incident on a phase sensitive receiving array can produce inaccuracies of the measured attenuation coefficient and phase velocity. The causal (Kramers-Kronig) link between these two quantities in the presence of phase distortion is investigated using two plastic polymer materials, Plexiglas and Lexan, that exhibit attenuation coefficients that increase linearly with frequency, in a fashion analogous to that of soft tissue. Flat and parallel plates were machined to have a step of a thickness corresponding to an integer number of half wavelengths within the bandwidth investigated, 3 to 7 MHz. Insonification of the stepped portion of each plate produces phase cancellation artifacts at the receiving aperture and, therefore, in the measured frequency dependent attenuation coefficient. Dispersion predictions using two different forms of the Kramers-Kronig relations were performed for the flat and the stepped regions of each plastic plate. Despite significant phase distortion and a detection system sensitive to these aberrations, the Kramers-Kronig link between the apparent attenuation coefficient and apparent phase velocity dispersion remains intact.     

The mean velocity profile of near-wall turbulent flow: is there anything in between the logarithmic and power laws?

The question of possible analytical forms for the mean velocity profile in a near-wall turbulent flow is addressed. An approach based on the use of dispersion relations for the flow velocity is developed in the context of a two-dimensional channel flow. It is shown that for an incompressible flow conserving vorticity, there exists a decomposition of the velocity field into rotational and potential components, such that the restriction of the former to an arbitrary cross section of the channel is a functional of the vorticity and velocity distributions over that cross section, while the latter is divergence-free and bounded downstream thereof. By eliminating the unknown potential component with the help of a dispersion relation, a nonlinear integro-differential equation for the flow velocity is obtained. It is then analysed within an asymptotic expansion in the small ratio v_*/U of the friction velocity to the mean flow velocity. Upon statistical averaging in the lowest nontrivial order, this equation relates the mean velocity to the cross-correlation function of the velocity fluctuations. Analysis of the equation reveals existence of two continuous families of solutions, one having the power-law near-wall asymptotic U ～ yⁿ, where y is the distance to the wall, n > 0, and the other, U ～ ln?^p(y/y₀), with y₀ = const and p ≥ 1. In the limit of infinite channel height, the exponent n turns out to be asymptotically a universal function of the Reynolds number, n ～ 1/ln?Re, whereas p → 1. Thus, the logarithmic profile (p = 1) is found to be a member of the power-log family whose members with p > 1 are intermediate between the power- and logarithmic-law profiles with respect to their slopes at large y. These results are discussed in the light of the existing controversy regarding experimental verification of the law of the wall.     

Effect of pressure on the M?ssbauer isomer shift and quadrupole splitting in Au(I)-cyanides

The effect of pressure on the Mössbauer isomer shift and quadrupole splitting was studied with the 77 keV resonance of¹⁹⁷Au in the Au(I)-cyanides AuCN and KAu(CN)₂ at 4.2 K under pressures up to 80 kbar. We observe an increase of the electron density and a decrease of the absolute value of the electric field gradient at the Au nuclei in both compounds with pressure. This variation is different from the correlation that has been established for these parameters within the chemical series of Au(I) compounds at ambient pressure. It indicates that the-bonding increases strongly under pressure. X-ray diffraction studies on AuCN under pressures up to 115 kbar together with investigations of the Goldanskii-Karyagin-effect on AuCN at ambient pressure support the previous assumption that the sign of the electric field gradient at the Au(I) sites is negative.     

Is there evidence for a 17 keV neutrino in the 35S β spectrum? The case of Ohi et al.

It is shown that there is a threshold 17 keV below the end point of the β spectrum of ³⁵S in the published work of Ohio et al. The distortion of the Kurie plot is consistent with that seen in the ³H β spectrum, strengthening the earlier suggestion that the distortion is due to the emission of a neutrino of mass 17 keV.     

Observation of a correlation between the dependences of the radiative decay time and intensity of the impurity core-valence luminescence on excitation energy in K1−x CsxCl and Rb1−x CsxCl mixed crystals

A study of the spectral and kinetic parameters of impurity core-valence luminescence (CVL) excited by synchrotron radiation in K_1−x Cs_xCl and Rb_1−x Cs_xCl mixed crystals is reported. The dependences of the intensity and radiative decay time τ of impurity CVL on exciting photon energy hν have been found to be correlated. It is concluded that the observed τ = f(hv) relation originates from nonradiative decay of core excitations near the surface, which govern also the excitation spectral features in this spectral region. Fiz. Tverd. Tela (St. Petersburg) 41, 1973–1975 (November 1999)     

Application of Pulse–Amplitude Modulated Fluorometry to Estimate the Effect of Volatile Organic Compounds and Benzo[a]Pyrene on the Functional Activity of Photosystem II in Leaves of Reed Fescue Festuca arundinacea Schreb.

Journal of Applied Spectroscopy - The mechanisms of action of toxic organic compounds (OC) (pentane, hexane, benzene, o-xylene, butyl acetate, and benzopyrene) on the reed fescue Festuca...     

Comments on ‘‘Effect of the surface free energy on the behaviour of surface and guided waves”, by V. Vlasie Belloncle,M. Rousseau,Ultrasonics, 45 (2006) 188–195

In this short communication, it is demonstrated that the main results obtained by the authors of the commented paper, ‘‘Effect of the surface free energy on the behaviour of surface and guided waves”, by V. Vlasie Belloncle, M. Rousseau Ultrasonics, 45 (2006) 188–195, have been well-established long before publication of this paper. Therefore, the claim to novelty asserted by the authors is incorrect.     

Rovibrational states of H+ 3. Part 2: The energy region between 9000 cm−1 and 13000 cm−1 including empirical corrections for the non-adiabatic effects

The first part of this series focused on the calculation of the rovibrational states of H⁺ ₃ in the energy region below 9000 cm^?1, where most of the experimentally determined and assigned term values are located. The theoretically justified empirical correction for the non-adiabatic coupling corrections, which was obtained and tested in that study is extended and applied here in the calculation of the rovibrational states of H⁺ ₃ to term values up to 13000 cm^?1, which is above the barrier to linearity. In particular, predictions are made for the 5v ₂ bands, which are the subject of current experimental investigations, hopefully aiding with our results in the assignment of the spectral lines observed.