Novel microscopic mechanism of intermixing during growth on soft metallic substrates

Generic computer simulations using empiric interatomic potentials suggest a new, collective mechanism that could be responsible for mixing at heteroepitaxial interfaces. Even if single adsorbate atoms diffuse by hopping on the substrate surface and do not mix at the terraces, two-dimensional islands formed by nucleation may become unstable above a certain critical size and explode upwards forming clusters of several atomic layers. This process is accompanied by strong distortions of the underlying atomic layers, and on soft materials it can result in surface etching and incorporation of substrate atoms into the islands.     

Observation of power-Law scaling for phase transitions in linear trapped ion crystals

We report an experimental confirmation of the power-law relationship between the critical anisotropy parameter and ion number for the linear-to-zigzag phase transition in an ionic crystal. Our experiment uses laser cooled calcium ions confined in a linear radio-frequency trap. Measurements for up to ten ions are in good agreement with theoretical and numeric predictions. Implications on an upper limit to the size of data registers in ion trap quantum computers are discussed.     

Upstream access and local customer networking in passive optical networks using a single wavelength-seeded reflective semiconductor optical amplifier

A scheme for upstream transmission and local area network emulation in passive optical networks using a single reflective semiconductor optical amplifier placed at the customer premises is proposed and experimentally demonstrated. In this scheme, two optical carriers are delivered to the optical network units from the central office for the transmission of upstream and local area network signals, respectively.     

Correlating the scattered intensities of P3HT and PCBM to the current densities of polymer solar cells

Grazing-incidence X-ray diffraction and rocking scans have quantified the structure of poly(3-hexylthiophene) and [6,6]-phenyl-C(61)-butyric acid methyl ester in the active layers of organic solar cells. Our study reveals that the device J(SC) correlates with the local structural development of pure PCBM and, to second order, the extent of out-of-plane P3HT π-stacking.     

Magnetic susceptibility measurement with a Dupont's thermogravimetric analyser

The adaptation of a Du Pont Thermogravimetric Analyser for the measurement of magnetic susceptibility as a function of temperature in the range – 80 °C to 300 °C is described.

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Zusammenfassung Die Adaptation des Du Pont's Thermogravimetric Analyzer zur Messung der magnetischen Suszeptibilität in Abhängigkeit von der Temperatur im Bereich von – 80° bis 300 °C wird mitgeteilt.

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–80°–300 °.

     

Composition assessment of ferric oxide by accurate peak fitting of the Fe 2p photoemission spectrum

A quantitative study of the surface composition of ferric oxide employing photoemission spectra is presented. It was possible to accurately reproduce the expected composition (Fe_2.00±0.05O₃) by modeling the background as a combination of Shirley‐type (Shirley–Vegh–Salvi–Castle) and slope backgrounds through the active approach. The line‐shape employed to fit apparent peak asymmetries was the double‐Lorentzian. It was possible to resolve a previously unreported satellite located at ~729 eV. Copyright © 2016 John Wiley & Sons, Ltd.     

Heteronuclear Nickel‐Iron Complexes and the Crystal Structure of [Fe2(CO)6(μ3‐S)2{Ni(dppe)}]

A series of heteronuclear nickel‐iron complexes [Fe₂(CO)₆(μ‐SH)(μ₃‐S){NiCl(PPh₃)₂}] ( 1 ), [Fe₂(CO)₆(μ‐SH)(μ₃‐S){NiCl(dppe)}] ( 2 ), [Fe₂(CO)₆(μ₃‐S)₂{Ni(PPh₃)₂}] ( 3 ), [Fe₂(CO)₆(μ₃‐S)₂{Ni(dppe)}] ( 4 ) and [Fe₂(CO)₆(μ‐SPh)(μ₃‐S){NiCl(dppe)}] ( 5 ) have been prepared. The structure of 4 has been determined by X‐ray crystallography. The central metal‐sulfur core of 4 has a trigonal bipyramidal shape with a NiFe₂ base plane with two axial sulfur atoms. Each iron atom is 5‐coordinate forming a distorted square pyramid; the nickel is square planar coordinated by two sulfur atoms and two phosphorus atoms.     

Electrochemical DNA biosensor for human papillomavirus 16 detection in real samples

An electrochemical DNA biosensor for human papillomavirus (HPV) 16 detection has been developed. For this proposed biosensor, l-cysteine was first electrodeposited on the gold electrode surface to form l-cysteine film (CYSFILM). Subsequently, HPV16-specific probe was immobilized on the electrode surface with CYSFILM. Electrochemistry measurement was studied by differential pulse voltammetry method (DPV). The measurement was based on the reduction signals of methylene blue (MB) before and after hybridization either between probe and synthetic target or extracted DNA from clinical samples. The effect of probe concentration was analyzed and the best results were seen at 1000 nM. The hybridization detection presented high sensitivity and broad linear response to the synthetic-target concentration comprised between 18.75 nM and 250 nM as well as to a detection limit of 18.13 nM. The performance of this biosensor was also investigated by checking probe-modified electrode hybridization with extracted DNA from samples. The results showed that the biosensor was successfully developed and exhibited high sensitivity and satisfactory selectivity to HPV16. These results allow for the possibility of developing a new portable detection system for HPVs and for providing help in making an effective diagnosis in the early stages of infection.     

Implementation of a genetically tuned neural platform in optimizing fluorescence from receptor-ligand binding interactions on microchips

This paper describes the use of a genetically tuned neural network platform to optimize the fluorescence realized upon binding 5-carboxyfluorescein-D-Ala-D-Ala-D-Ala (5-FAM-(D-Ala)(3) ) (1) to the antibiotic teicoplanin from Actinoplanes teichomyceticus electrostatically attached to a microfluidic channel originally modified with 3-aminopropyltriethoxysilane. Here, three parameters: (i) the length of time teicoplanin was in the microchannel; (ii) the length of time 1 was in the microchannel, thereby, in equilibrium with teicoplanin, and; (iii) the amount of time buffer was flushed through the microchannel to wash out any unbound 1 remaining in the channel, are examined at a constant concentration of 1, with neural network methodology applied to optimize fluorescence. Optimal neural structure provided a best fit model, both for the training set (r(2) = 0.985) and testing set (r(2) = 0.967) data. Simulated results were experimentally validated demonstrating efficiency of the neural network approach and proved superior to the use of multiple linear regression and neural networks using standard back propagation.