Higher Schläfli Formulas and Applications

The classical Schläfli formula relates the variations of the dihedral angles of a smooth family of polyhedra in a space-form to the variation of the enclosed volume. We give higher analogues of this formula: for each p, we prove a simple formula relating the variation of the volumes of the codimension p faces to the variation of the 'curvature' – the volumes of the duals of the links in the convex case – of codimension p+2 faces. It is valid also for ideal polyhedra, or for polyhedra with some ideal vertices. This extends results of Suárez-Peiró. The proof is through analoguous smooth formulas. Some applications are described.     

Oxone/iron(II) sulfate/graphite oxide as a highly effective system for oxidation of alcohols under ultrasonic irradiation

Oxone, in the presence of a catalytic amount of iron(II) sulfate and graphite oxide, oxidizes efficiently alcohols into their corresponding carboxylic acid or ketone compounds at room temperature in short reaction times and in good to quantitative yields under ultrasonic irradiation.     

Novel sheathless CE-MS interface as an original and powerful infusion platform for nanoESI study: from intact proteins to high molecular mass noncovalent complexes

Development of nano-electrospray (nanoESI) sources allowed to increase significantly the sensitivity which is often lacking when studying biological noncovalent assemblies. However, the flow rate used to infuse the sample into the mass spectrometer cannot be precisely controlled with nanoESI and the robustness of the system could represent an issue. In this study, we have used a sheathless capillary electrophoresis–mass spectrometry (CESI) prototype as a nanoESI infusion device. The hydrodynamic mobilization of the capillary content was characterized and the ability of the system to generate a stable electrospray under controlled flow rate conditions ranging from 4 up to 900 nL/min was demonstrated. The effect of the infusing flow rate on the detection of an intact model protein analyzed under native conditions was investigated. Results demonstrated a significant increase in sensitivity of 46-fold and a signal-to-noise ratio improvement of nearly 5-fold when using an infusing flow rate from 456.9 down to 13.7 nL/min. The CESI prototype was further used to detect successfully the β ring homodimer in its native conformation. Obtained results were compared with those achieved with conventional ESI. Intensity signals were increased by a factor of 5, while sample consumption decreased 80 times. β ring complexed with the P14 peptide was also studied. Finally, the CESI interface was used to observe the quaternary structure of native hemocyanins from Carcinus maenas crabs; this high molecular complex coexisting under various degrees of complexation and resulting in masses ranging from 445 kDa to 1.34 MDa.     

A convenient and efficient one-pot method for the synthesis of novel acridine-calix[4]arene derivatives as new DNA binding agents via multicomponent reaction

A new approach is applied for the synthesis of novel acridine-calix[4]arene derivatives via a multicomponent reaction. These compounds have been characterised by ¹H NMR, ¹³C NMR and HR-MS. Our binding studies between acridine-functionalised calix[4]arenes and calf thymus DNA (CT-DNA) via fluorescence titration show that these compounds have a good affinity to CT-DNA.     

Static and dynamic dielectric effects in the vicinity of the isotropic to nematic phase transition in 7CB

Static and dynamic dielectric measurements were performed with very high accuracy on a mesogenic compound n‐heptylcyanobiphenyl (7CB) in the isotropic (I) and nematic (N) phases. The critical‐like temperature behaviour of the static permittivity of isotropic 7CB in the vicinity of the I–N phase transition can be described with the critical exponent close to 0.5, indicating the tricritical nature of the transition. Anomalously slow rotational diffusion (subdiffusion), characterized by a fractal value of the diffusion exponent α, is observed in the vicinity of the I–N transition with a lambda‐like profile of the exponent temperature dependence.     

Fractional Stokes-Einstein-Debye relation and orientational entropy effects in strongly hydrogen-bonded liquid amides

The impedance spectroscopy studies performed for two strongly hydrogen-bonded liquid amides: N-methylpropionamide (NMP, CH(3)·NH·CO·C(2)H(5)) and N-ethylacetamide (NEA, C(2)H(5)·NH·CO·CH(3)) have shown that the two centers of the peptide linkage, -NH·CO-, active in the C=OH-N hydrogen bonds formation, exhibit quite different sensibilities to the steric screening effects. In contrast to the oxygen atom, a relatively small change (CH(3)- to C(2)H(5)-) in the screening of the hydrogen atom leads to an essential decrease of the degree of the amide self-association. As a consequence, both the static dielectric permittivity and the orientational entropy increment of NEA are essentially lower than those of NMP. However, it was found that the dynamic processes studied are only weakly influenced (in the case of dc conductivity, σ(DC)) or totally not influenced (the dielectric relaxation time, τ(D)) by the different degrees of NMP and NEA self-association. The experiment shows that for both the amides, the logσ(DC) vs. logτ(D) dependence is nonlinear and can be described with the fractional Stokes-Einstein-Debye relation, σ(DC)τ ? const, with the exponent s varying from about -0.8 to about -0.6 in the temperature range from 5 °C to 110 °C.     

Dynamics of unfolded protein transport through an aerolysin pore

Protein export is an essential mechanism in living cells and exported proteins are usually translocated through a protein-conducting channel in an unfolded state. Here we analyze, by electrical detection, the entry and transport of unfolded proteins, at the single molecule level, with different stabilities through an aerolysin pore, as a function of the applied voltage and protein concentration. The frequency of ionic current blockades varies exponentially as a function of the applied voltage and linearly as a function of protein concentration. The transport time of unfolded proteins decreases exponentially when the applied voltage increases. We prove that the ionic current blockade duration of a double-sized protein is longer than that assessed for a single protein supporting the transport phenomenon. Our results fit with the theory of confined polyelectrolyte and with some experimental results about DNA or synthetic polyelectrolyte translocation through protein channels as a function of applied voltage. We discuss the potential of the aerolysin nanopore as a tool for protein folding studies as it has already been done for α-hemolysin.     

Experimental investigation on the sensible effectiveness of LiCl wheel

Experimental investigation on the sensible effectiveness of LiCl wheel is reported. The measurements were made for balanced flow (C* = 1) for a wide range of rotational speed 0–10 rpm, regeneration temperature of 50–70°C and airflow rate 150–550 kg/h. The results revealed that the operation rotational speed for LiCl wheel is about 5 rpm which is significantly lower that for Silica gel wheel. It is also found that the sensible effectiveness is independent of the regeneration temperature. The experimental results are also fitted to the existing correlation of Simonson et al. (ASHRAE Trans 106(1):301–310, 2000). For the range of the applicability of the correlation, most of the experimental data fit the correlation within an error band of ±5%.     

Spectral discrimination of benign and malignant prostate tissues--a preliminary report

In this preliminary report, benign (n=8) and malignant (n=5) prostate tissues, in vitro, have been taken through autofluorescence spectroscopy. Employing Stokes' shift spectra and fluorescence emission spectra as tools of analysis, we were able to discriminate the two sets of tissues with sensitivity and specificity in excess of 85%. When the excised prostate chips were scanned with a spatial resolution of 1 mm, the epicenter of malignancy also could be delineated.     

Comparative analysis of MIMO-based FSO and MIMO-based MGDM communications

Optical Review - The ever-growing need for high data rate, bandwidth efficiency, reliability, less complexity, and less power consumption in the communication systems is on the increase. Modern...