Structural and optical properties of a-Si1−xCx:H films synthesized by dc magnetron sputtering technique

Hydrogenated amorphous SiC films (a-Si_1−xC_x:H) were prepared by dc magnetron sputtering technique on p-type Si(1 0 0) and corning 9075 substrates at low temperature, by using 32 sprigs of silicon carbide (6H-SiC). The deposited a-Si_1−xC_x:H film was realized under a mixture of argon and hydrogen gases. The a-Si_1−xC_x:H films have been investigated by scanning electronic microscopy equipped with an EDS system (SEM-EDS), X-ray diffraction (XRD), secondary ions mass spectrometry (SIMS), Fourier transform infrared spectroscopy (FTIR), UV-vis-IR spectrophotometry, and photoluminescence (PL). XRD results showed that the deposited film was amorphous with a structure as a-Si_0.80C_0.20:H corresponding to 20 at.% carbon. The photoluminescence response of the samples was observed in the visible range at room temperature with two peaks centred at 463 nm (2.68 eV) and 542 nm (2.29 eV). In addition, the dependence of photoluminescence behaviour on film thickness for a certain carbon composition in hydrogenated amorphous SiC films (a-Si_1−xC_x:H) has been investigated.     

Stability analysis of neutral type systems in Hilbert space

The asymtoptic stability properties of neutral type systems are studied mainly in the critical case when the exponential stability is not possible. We consider an operator model of the system in Hilbert space and use recent results on the existence of a Riesz basis of invariant finite-dimensional subspaces in order to verify its dissipativity. The main results concern the conditions of asymptotic non-exponential stability. We show that the property of asymptotic stability is not determinated only by the spectrum of the system but essentially depends on the geometric spectral characteristic of its main neutral term. Moreover, we present an example of two systems of neutral type which have both the same spectrum in the open left-half plane and the main neutral term but one of them is asymptotically stable while the other is unstable.     

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.     

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...