A practical entry to C18-constrained-E-ring analogues of methyllycaconitine (MLA): a concise new stereoselective approach to 8-oxa-decahydroisoquinolines accompanied by a simple microwaves-assisted synthesis of the succinimidobenzoate appendage of MLA

A Mannich-type intramolecular cyclization afforded access to a 8-oxa-decahydroisoquinoline heterocyclic system. Good stereoselectivity was observed. A promising microwave-assisted synthesis of the methylsuccinimidobenzoate moiety of methyllycaconitine has also been carried out.     

Photonic Metal Bandgap Structure for Intersubband Detection

We would like to present here a geometry of Quantum Well Infrared Photodetectors (QWIPs) for increasing the detectivity. It consists of a mesa (a squared etched pixel) with a metal grating on top of it. The grating concentrates the electromagnetic field in the electric area defined by proton implantation. We focus on the design of the grating based on Floquet Bloch S-Matrix calculations. For the optimisation, the relation between the electronic structure of the detector and the pixel geometry is highlighted.     

On the use of polycapillary structures to improve laboratory Energy-Dispersive X-ray Diffractometry and Reflectometry

One of the major limits of the laboratory X-ray sources is represented by their low photon flux which induces many researchers to move to synchrotron beamlines. From this point of view, polycapillaries lenses represent an extraordinary tool to improve the performances of laboratory machine and, indeed, several models of polycapillary optics-based instruments, such as diffractometers, spectrometers etc., are currently available on the market. In this work, the application of polycapillary optics to a particular kind of non-commercial X-ray instruments, namely the Energy-Dispersive X-ray Diffractometers and Reflectometers, is proposed. The advantages and limits of the use of polycapillaries are discussed and the results of preliminary experiments are shown.     

Stability-Indicating LC Determination of a New Antihypertensive,Olmesartan Medoxomil in Tablets

A stability-indicating liquid chromatographic method was developed and validated for quantitative determination of olmesartan medoxomil (OLM) in coated tablets in the presence of degradation products generated under stress conditions. An isocratic LC separation was performed using a Phenomenex RP-18 column using a mobile phase consisting of water:triethylamine:acetonitrile (60:0.3:40 v/v/v, pH adjusted to 6.3 with phosphoric acid). The flow rate was 1.2 mL min⁻¹ and the detection was achieved with a photodiode array detector set at 257 nm. The response was linear over a range of 10.0 to 30.0 μg mL⁻¹ (r = 0.9999). The specificity and stability-indicating capability of the method was verified subjecting the reference substance and drug product to hydrolytic, oxidative, photolytic, and thermal stress conditions. The method showed a good and consistent recovery (100.2%) with low intra- and inter-day relative standard deviation (RSD) (≤1.0%). A considerable degradation occurred in all stress conditions and the degradation product was well resolved from the main peak. There was no interference of the excipients in the determination of the active pharmaceutical ingredient. Thus, the proposed method was found to be stability-indicating and can be used for routine analysis for quantitative determination of OLM in coated tablets without the interference of major degradation products.

     

Influence of pressure and atomizer length on absorption curves in ETA-AAS measurements for standardless analysis

A new method for standardless analysis in electrothermal atomic absorption spectroscopy has been recently proposed whose implementation requires the use of special atomizers and power supplies not available in the market. Up to now, with the proposed method, only volatile elements have been determined with good results because it can be applied only if all atoms injected are simultaneously present in the atomizer for a time interval sufficiently long that a good value of absorbance can be measured. This can be obtained if the heating rate is sufficiently high and the removal of atoms from the atomizer slow. From a theoretical model based only on diffusion, it can be deduced that the possibility of standardless analysis in the mode described above can be enhanced if the length of the atomizer is increased and the diffusion coefficient of the analyte is decreased. From the results obtained by comparing data from atomizers of 36 and 50 mm in length and at different pressures, it can be inferred that the removal mechanism is basically controlled by diffusion but that other mechanisms, like convection, are also present. Received: 2 May 1997 / Revised: 15 December 1997 / Accepted: 15 January 1998     

Blow-up sets for linear diffusion equations in one dimension

We consider the heat equation in the half-line with Dirichlet boundary data which blow up in finite time. Though the blow-up set may be any interval [0,a], a ? [0,￥]a\in[0,\infty] depending on the Dirichlet data, we prove that the effective blow-up set, that is, the set of points x 3 0x\ge0 where the solution behaves like u(0,t), consists always only of the origin. As an application of our results we consider a system of two heat equations with a nontrivial nonlinear flux coupling at the boundary. We show that by prescribing the non-linearities the two components may have different blow-up sets. However, the effective blow-up sets do not depend on the coupling and coincide with the origin for both components.     

The cubic period-distance relation for the Kate reversible pendulum

We describe the correct cubic relation between the mass configuration of a Kater reversible pendulum and its period of oscillation. From an analysis of its solutions we conclude that there could be as many as three distinct mass configurations for which the periods of small oscillations about the two pivots of the pendulum have the same value. We also discuss a real compound Kater pendulum that realizes this property.     

Flow Cytometric Technique for Quantitating Cytotoxic Response to Photodynamic Therapy

Abstract— A simple flow cytometric technique for rapid measurement of multilog cytotoxic responses to photosensitization of cellular systems is described. This technique is particularly useful for cell lines with a low colony-forming efficiency, for which a nonclonogenic assay is required. The assay separates cell-sized objects from cellular debris by gating on forward scatter versus side scatter, identifies viable cells by positive calcein AM and negative ethidium homodimer-1 staining and measures cell concentration relative to an internal standard of polystyrene beads. Large numbers of cells can be analyzed rapidly.
Two patient-derived small cell lung cancer cell lines, NCI-H209 and SV-E, were used to test the technique. Photoradiation survival curves of the response of these cell lines to 5-aminolevulinic acid-induced protoporphyrin IX photosensitization correlated with the extent of photosensitizer accumulation. There was good agreement between the results obtained using the tritiated thymidine incorporation assay and the flow cytometric cytotoxicity assay. The technique can be used to measure cytotoxic responses to photosensitization of cell lines regardless of their plating efficiencies.     

Exact approaches for lifetime maximization in connectivity constrained wireless multi-role sensor networks

In this paper, we consider the duty scheduling of sensor activities in wireless sensor networks to maximize the lifetime. We address full target coverage problems contemplating sensors used for sensing data and transmit it to the base station through multi-hop communication as well as sensors used only for communication purposes. Subsets of sensors (also called covers) are generated. Those covers are able to satisfy the coverage requirements as well as the connection to the base station. Thus, maximum lifetime can be obtained by identifying the optimal covers and allocate them an operation time. The problem is solved through a column generation approach decomposed in a master problem used to allocate the optimal time interval during which covers are used and in a pricing subproblem used to identify the covers leading to maximum lifetime. Additionally, Branch-and-Cut based on Benders’ decomposition and constraint programming approaches are used to solve the pricing subproblem. The approach is tested on randomly generated instances. The computational results demonstrate the efficiency of the proposed approach to solve the maximum network lifetime problem in wireless sensor networks with up to 500 sensors.