Intrinsic integrated optical temperature sensor based on waveguide bend loss

Curvature of a multimode integrated optical waveguide reduces the numerical aperture and induces radiation losses. In this paper, we study this phenomenon and we present a geometrical approach to calculate the local numerical aperture and the intensity attenuation. We exploit the bending effect on the local numerical aperture to make a new intrinsic temperature sensor. The simulation results are validated for the silica/silicone integrated optical case. The principal performances of the silica/silicone temperature sensor are the extended temperatures range (−50 to 200 °C) with an excellent linearity response (1%) between 20 and 200 °C.     

Substrate structural effects in micellar catalysis with perfluorooctanoic acid

Rates of hydrolysis of a series of hydroxamic acids in aqueous acetonitrile, with perfluorooctanoic acid serving as a reactive counterion surfactant, have been determined. The pseudophase ion exchange model satisfactorily explains the surfactant effects. Variation in the structure of the hydrophobic moiety of the hydroxamic acid substrates was obtained by the incorporation of different chain lengths and differently substituted aryl groups into the substrate. The major influence of the change in substrate structure is on the binding constant for binding of the substrate to the surfactant aggregate. The number of substitutions on the aryl ring appears to be more important than the total number of carbon atoms in the substrate. © John Wiley & Sons, Inc.     

On constructing bases for ideals in polynomial rings over the integers

The author defines canonical bases for ideals in polynomial rings over Z and develops an algorithm for constructing such a basis for a given ideal. Results of previous authors are discussed and a comparison between those and the results obtained here is included.     

Synthesis,spectroscopic investigations,and computational study of 4-((9,10-dioxo-9,10-dihydroanthracen-1-yl)oxy)-3-methoxybenzaldehyde

4-((9,10-dioxo-9,10-dihydroanthracen-1-yl)oxy)-3-methoxybenzaldehyde has been synthesized in an attempt to obtain a new photochromic compound. The optimized molecular structure, mole fractions of title compound in trans and ana forms have been investigated. UV-visible spectra of the compound were also recorded. Upon irradiation with 300 nm light, the camel solid turned orange, in which a visible absorption band was observed at 475 nm. The electronic properties, such as HOMO, LUMO and band gap energies were obtained by the time-dependent DFT (TD-DFT) approach. The predicted nonlinear optical properties of the title compound are much greater than those of urea. Transition structures were calculated by QST3 and IRC methods which yielded the potential energy surface and activation energy.     

Synthesis of poly(ether esters) from reaction of alpha-cyano-4-hydroxycinnamic acid and group IVB metallocenes

Poly(ether esters) are rapidly synthesized in moderate yield employing the interfacial polycondensation reaction system from the reaction of alpha-cyano-4-hydroxycinnamic acid and Group IVB metallocenes. The products are high polymers. Infrared spectroscopy shows the formation of new bands derived from the M-O and M-O(CO) linkages. It also shows that the products exist as alternating M-O and M-O(CO) linkages. The products show outstanding inhibition of a variety of cancer cell lines including two pancreatic cancer cell lines. EC₅₀ values for the polymers are in the nanogram/mL range. The ability to inhibit the cancer cell lines is generally Hf>Zr>Ti. Thus, future synthesis and testing might consider using compounds containing hafnocene and zirconocene in addition to the titanocene moiety.     

Photochemistry of ethyl chloride caged in amorphous solid water

Caging and photo-induced decomposition of ethyl chloride molecules (EC) within a layer of amorphous solid water (ASW) on top of clean and oxygen-covered Ru(001) under ultra-high vacuum (UHV) conditions are presented. The caged molecules were estimated to reside 1.5 +/- 0.2 nm above the solid surface, based on parent molecule thermal decomposition on the clean ruthenium. Dissociative electron attachment (DEA) of the caged molecules following 193 nm laser irradiation, result in initial fragmentation to ethyl radical and chloride anion. It was found that photoreactivity on top of the clean ruthenium surface (Ru) is twenty times faster than on the oxygen-covered surface (O/Ru), with DEA cross sections: sigma(Ru) = (3.8 +/- 1) x 10(-19) cm(2) and sigma(O/Ru) = (2.1 +/- 0.3) x 10(-20) cm(2). This difference is attributed to the higher work function of oxygen-covered ruthenium, leading to smaller electron attachment probability due to mismatch of the ruthenium photo-electron energy with the adsorbed EC excited electron affinity levels. EC molecules fragmented within the cage, result in post-irradiation TPD spectra that reveal primarily C(4)H(8), C(3)H(5) and C(3)H(3), without any oxygen-containing molecules. Unique stabilization of the photoproducts has been observed with the first layer of water molecules in direct contact with the substrate, desorbing near 180 K, a significantly higher temperature than the desorption of fully caged molecules. This study may contribute for understanding stratospheric photochemistry and processes in interstellar space.     

The potential off-target neuroprotective effect of sister gliflozins suggests their repurposing despite not crossing the blood–brain barrier: From bioanalytical assay in rats into theory genesis

Gliflozins are successfully marketed antidiabetic agents with a reported neuroprotective effect, and this study tests their blood–brain barrier crossing ability. Henceforward, a computational hypothesis interpreting their effects was reasonable after failure to cross into the brain. A chromatographic bioassay for canagliflozin, dapagliflozin, and empagliflozin was developed, validated, and applied to the rat's and rat's plasma and brain. HPLC method robustness was tested over two levels using Design of Experiment on MINITAB. It is the first method for gliflozins’ detection in rats’ brain tissue. The method was applied on 18 rats and six for each drug. Concentrations in plasma were determined but neither of them was detected in brain at the described chromatographic conditions. A computational study for the three drugs was endorsing two techniques. First, ligand-based target fishing reveals possible targets for gliflozins. They showed an ability to bind with human equilibrative nucleoside transporter 1, a regulator of adenosine extracellularly. Second, a docking study was carried out on this protein receptor. Results showed perfect alignment with a minimum of one hydrogen bond. Dapagliflozin achieved the lowest energy score with two hocking hydrogen bonds. This is proposing gliflozins ability to regulate equilibrative nucleoside transporter 1 receptors in peripheries, elevating the centrally acting neuroprotective adenosine.     

Comparative Study of Polymer Nanoparticles on the Basis of Caprolactone–Polyvinyl Alcohol Mixtures with an Encapsulated Antitumor Preparation by Atomic Force Microscopy,X-Ray Diffraction,and Dynamic Light Scattering

Technical Physics - The morphology, structure, and optical properties of composites with biodegradable polymeric particles, which are based on poly-ε-caprolactone–polyvinyl alcohol...