Dugundji’s theorem for cone metric spaces

In this work, we will prove the Dugundji extension theorem for the cone metric space. It is heavily reliant on the paracompactness of the cone topology that is proved by Ayse Sönmez in the paper Sönmez (2010) [11].     

Hand-held syringe as a portable plastic pump for on-chip continuous-flow PCR: miniaturization of sample injection device

On-chip continuous-flow polymerase chain reactions (PCRs) generally require peripheral apparatus such as a pump for injecting a sample liquid into the fluidic channel. This makes the overall instrumentation bulky, limiting integration. In this study, we propose a new scheme for injecting a sample employing a hand-held syringe as a portable plastic pump, and apply it to an on-chip continuous-flow PCR. In the proposed injection scheme, sample actuation was realized inside a highly gas-permeable and blunt-ended fluidic conduit connected to a hand-held plastic syringe filled with compressed air. In this system, the degree of air diffusion via the walls of the gas-permeable conduit becomes greater in the anterior (closer to the outlet) end of the sample plug than the posterior (closer to the inlet) end, because a relatively larger quantity of air is retained inside the syringe at the posterior end of the sample plug. This creates a pressure gradient at the inlet and outlet of the fluidic conduit and propels the sample forward toward the outlet. Preliminary experiments were performed for the quantitative analyses and evaluation of the proposed sample injection scheme using gas-permeable silicone tubes. As practical applications, a 230 bp gene fragment from a plasmid vector and the first 282 bp of the interferon-beta (IFN-β) promoter from a human genomic DNA were successfully amplified on a microdevice coupled with a hand-held syringe as a portable sample actuation device, greatly enhancing device portability for on-site analyses.     

Flow-through PCR on a 3D qiandu-shaped polydimethylsiloxane (PDMS) microdevice employing a single heater: toward microscale multiplex PCR

Consistent temperature control in an on-chip flow-through polymerase chain reaction (PCR) employing two or more heaters is one of the main obstacles for device miniaturization and integration when realizing micro total analysis systems (μTAS), and also leads to operational complexity. In this study, we propose a qiandu (right triangular prism)-shaped polydimethylsiloxane (PDMS) microdevice with serpentine microchannels fabricated on its slanted plane, and apply the device for an on-chip flow-through PCR employing a single heater. The inclined nature of the qiandu-shaped microdevice enables the formation of a surface temperature gradient along the slanted plane of the microdevice in a height-dependent manner by the use of a single heater, and enables liquid to traverse over wide ranges of temperatures, including the three temperature zones--denaturation, annealing, and extension temperatures--required in a typical PCR. The feasibility of the qiandu-shaped PDMS microdevice as a versatile platform for performing a flow-through PCR was examined by employing multiple templates and varying the inclination angle of the device. In addition, the potential of performing a multiplex PCR using a single qiandu-shaped PDMS microdevice was explored. A 409 bp long gene fragment effective as a marker for diagnosing lung cancer and a 230 bp long gene fragment from a plasmid vector were simultaneously amplified in less than 25 min on a single microdevice, paving the way for a microscale, multiplex PCR on a single device employing a single heater.     

Computing the non-computable

We explore in the framework of quantum computation the notion of computability, which holds a central position in mathematics and theoretical computer science. A quantum algorithm that exploits the quantum adiabatic processes is considered for Hilbert's tenth problem, which is equivalent to the Turing halting problem and known to be mathematically non-computable. Generalized quantum algorithms are also considered for some other mathematical non-computables in the same and in different non-computability classes. The key element of all these algorithms is the measurability of both the values of physical observables and the quantum-mechanical probability distributions for these values. It is argued that computability, and thus the limits of mathematics, ought to be determined not solely by mathematics itself but also by physical principles.     

All-fiber bidirectional passively mode-locked ring laser

We report the design and operation of a novel all-fiber bidirectional passively mode-locked ring laser. An erbium-doped fiber was chosen as the active element in a ring cavity arrangement. A short segment of a fiber taper embedded in carbon nanotubes/polymer composite, acting as a saturable absorber, was used to enable bidirectional mode locking. The laser generates two stable femtosecond pulse trains in opposite directions. A beat note of about 2 MHz, having a bandwidth of less than 2 kHz, is measured when the pulses propagating in opposite directions are (temporally) overlapped at a photodetector. We believe this device will find important applications in precision rotation sensing.     

A method to improve crystal quality of CZTSSe absorber layer

Journal of Sol-Gel Science and Technology - In this work, a fabrication process of high crystallinity CZTSSe absorber layer is presented. The CZTS structure is firstly prepared by spin-coating...     

Development of empirical potentials for sodium borosilicate glass systems

New parameter values are proposed for the empirical potentials used to describe SiO₂-B₂O₃-Na₂O alkali borosilicate glass systems. They are based on Buckingham potentials, but include dependence between the fitting parameters and the glass chemical composition to improve the representation of the complex environment around the boron atoms. In particular, the boron anomaly (observed when the [Na₂O]/[B₂O₃] ratio varies) is correctly reproduced. The structural and mechanical properties of a wide range of glass compositions and of reedmergnerite crystals are correctly simulated: bond distances, mean angles, densities, elastic moduli. The deviations from the experimental values are small.     

Plasmonic tuning of aluminum doped zinc oxide nanostructures by atomic layer deposition

Currently there is a strong interest in plasmonic materials operating in the near‐infrared (NIR), however, conventional metals such as gold and silver possess high optical losses in this region. In this work we demonstrate localized surface plasmon resonances (LSPRs) with low loss in the NIR region by utilizing atomic layer deposition to deposit thin films of aluminium doped zinc oxide onto silicon nanopillars created via nanopshere lithography. The deposited films have excellent conformality and the LSPRs can be tuned from the mid‐infrared to the NIR by controlling the doping concentration, deposition temperature and nanostructure morphology. (© 2014 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim)     

A note on the theory of fast money flow dynamics

The gauge theory of arbitrage was introduced by Ilinski in [K. Ilinski, preprint arXiv:hep-th/9710148 (1997)] and applied to fast money flows in [A. Ilinskaia, K. Ilinski, preprint arXiv:cond-mat/9902044 (1999); K. Ilinski, Physics of finance: gauge modelling in non-equilibrium pricing (Wiley, 2001)]. The theory of fast money flow dynamics attempts to model the evolution of currency exchange rates and stock prices on short, e.g. intra-day, time scales. It has been used to explain some of the heuristic trading rules, known as technical analysis, that are used by professional traders in the equity and foreign exchange markets. A critique of some of the underlying assumptions of the gauge theory of arbitrage was presented by Sornette in [D. Sornette, Int. J. Mod. Phys. C 9, 505 (1998)]. In this paper, we present a critique of the theory of fast money flow dynamics, which was not examined by Sornette. We demonstrate that the choice of the input parameters used in [K. Ilinski, Physics of finance: gauge modelling in non-equilibrium pricing (Wiley, 2001)] results in sinusoidal oscillations of the exchange rate, in conflict with the results presented in [K. Ilinski, Physics of finance: gauge modelling in non-equilibrium pricing (Wiley, 2001)]. We also find that the dynamics predicted by the theory are generally unstable in most realistic situations, with the exchange rate tending to zero or infinity exponentially.