Efficient estimation of continuous phase modulation with unknowncarrier phase

An efficient algorithm is presented for the estimation of continuous phase modulation (CPM) sequences over the Gaussian channel with unknown carrier phase. It operates on the excess phase trellis like the Viterbi algorithm, except that it is not a maximum-likelihood (ML) estimator. Its decision metric for survivor selection at each node is chosen so that it achieves the node error event probability of coherent ML estimation in the limit as the carrier phase remains constant over a long interval, so that the observation interval for forming the metric can be made large. It is shown for the case of minimum-shift-keying (MSK) that the bit-error probability (BEP) of perfectly coherent ML estimation is attained     

A Non-cooperative Uplink Power Control for CDMA Wireless Communication System

In this project, the main focus is to enhance the existing power control algorithm that is applied in a single cell of CDMA network. Nash algorithm is selected and is further improved with modification of its cost function with a value as power of target SINR, which to reduce the SINR error at first iteration, so as to increase the rate of convergence effectively. Decision of a value is important to ensure the SINR error is reduced at first iteration. The uniqueness and algorithm convergence of enhanced cost function is proven with certain conditions requirements. Therefore, enhanced Nash algorithm (ENA) is proposed which only applicable in first iteration of power control method. The rest of iterations are applied by Nash algorithm due to its better convergence to target SINR. After simulations, with consideration of Rayleigh and Rician fading channels, a significant increase in rate of convergence while maintaining the SINR with error less than 0.01 is shown. The transmitted power is lower in some scenarios, or with very slight reduction less than 0.5%. The SINR error at first iteration is reduced about 20% more by using ENA. In overall, ENA has better performance than the existing Nash algorithm in terms of transmitted power and rate of convergence, without compromising SINR.

     

New elements in the interreceptor matrix: a comparative study of Megavilli and Landolt's club

Megavilli and Landolt's clubs were reported in the interreceptor matrix of the retina of the goldfish and neonatal rat for the first time. Megavilli encroach onto the inner or outer segments of photoreceptors and were different from microvilli. Landolt's clubs were not present in the adult rat but only in the adult goldfish.     

An expert fuzzy rule-based system for closed-loop supply chain performance assessment in the automotive industry

Closed-loop supply chain management has been identified as an efficient, effective and economical strategy towards environmental sustainable practices in manufacturing companies. Without a formidable closed-loop supply chain to complement green supply chain management, most of the goals will not be achieved. A performance evaluation system is crucial for achieving a successful closed-loop supply chain in the automotive industry. Hence, a suitable expert fuzzy rule-based system for evaluation was developed in this study using Visual Basic.Net. The fuzzy rules and arithmetic used were described. The resulting performance measurement system was evaluated using a case study company from the automotive industry. The study culminated with recommendations and proposal of directions for future studies.     

A Novel Lipase from Lasiodiplodia theobromae Efficiently Hydrolyses C8-C10 Methyl Esters for the Preparation of Medium-Chain Triglycerides’ Precursors

Medium-chain triglycerides (MCTs) are an emerging choice to treat neurodegenerative disorders such as Alzheimer’s disease. They are triesters of glycerol and three medium-chain fatty acids, such as capric (C8) and caprylic (C10) acids. The availability of C8–C10 methyl esters (C8–C10 ME) from vegetable oil processes has presented an opportunity to use methyl esters as raw materials for the synthesis of MCTs. However, there are few reports on enzymes that can efficiently hydrolyse C8–C10 ME to industrial specifications. Here, we report the discovery and identification of a novel lipase from Lasiodiplodia theobromae fungus (LTL1), which hydrolyses C8–C10 ME efficiently. LTL1 can perform hydrolysis over pH ranges from 3.0 to 9.0 and maintain thermotolerance up to 70 °C. It has high selectivity for monoesters over triesters and displays higher activity over commercially available lipases for C8–C10 ME to achieve 96.17% hydrolysis within 31 h. Structural analysis by protein X-ray crystallography revealed LTL1’s well-conserved lipase core domain, together with a partially resolved N-terminal subdomain and an inserted loop, which may suggest its hydrolytic preference for monoesters. In conclusion, our results suggest that LTL1 provides a tractable route towards to production of C8–C10 fatty acids from methyl esters for the synthesis of MCTs.     

Hydrophilic modification of neural microelectrode arrays based on multi-walled carbon nanotubes

To decrease the impedance of microelectrode arrays, for neuroscience applications we have fabricated and tested MEA based on multi-walled carbon nanotubes. With decreasing physical size of a microelectrode, its impedance increases and charge-transfer capability decreases. To decrease the impedance, the effective surface area of the electrode must generally be increased. We explored the effect of plasma treatment on the surface wettability of MWCNT. With a steam-plasma treatment the surface of MWCNT becomes converted from superhydrophobic to superhydrophilic; this hydrophilic property is attributed to?-OH bonding on the surface of MWCNT. We reported the synthesis at 400?°C of MWCNT on nickel-titanium multilayered metal catalysts by thermal chemical vapor deposition. Applying plasma with a power less than 25?W for 10?s improved the electrochemical and biological properties, and circumvented the limitation of the surface reverting to a hydrophobic condition; a hydrophilic state is maintained for at least one month. The MEA was used to record neural signals of a lateral giant cell from an American crayfish. The response amplitude of the action potential was about 275?μV with 1?ms period; the recorded data had a ratio of signal to noise up to 40.12?dB. The improved performance of the electrode makes feasible the separation of neural signals and the recognition of their distinct shapes. With further development the rapid treatment will be useful for long-term recording applications.     

Fabrication of well-crystallized mesoporous ZrO2 thin films via Pluronic P123 templated sol–gel route

Mesoporous zirconia (ZrO₂) thin films were prepared by dip-coating via Pluronic P123 templated sol–gel route. ZrOCl₂·8 H₂O was used as zirconium (Zr) precursors. Annealing of as-coated ZrO₂ thin films is important in order to stiffen the respective films and to remove the Pluronic P123. The mesoporous structure and crystallite size of ZrO₂ were characterized systematically by field-emission scanning electron microscope (FESEM), both low- and wide-angle X-ray diffraction, thermal analysis technique and Brunauer–Emmett–Teller method. At annealing temperature of 400 °C, amorphous ZrO₂ was transformed into tetragonal phase of ZrO₂ (t-ZrO₂). At 450 °C, t-ZrO₂ and monoclinic phase of ZrO₂ (m-ZrO₂) were obtained. By altering heating rate during annealing, volume fraction of t-ZrO₂ and m-ZrO₂ was changed. FESEM images showed that disordered mesostructures of ZrO₂ were formed after annealing. The surface area of mesoporous ZrO₂ obtained ranges from 54.33 to 93.39 m²/g.     

Physico-chemical studies of amorphous carbon nanotubes synthesized at low temperature

This work provides better understanding on the nature of amorphous carbon nanotubes, which are synthesized via a simple chemical route. Amorphous carbon nanotubes (α-CNTs) are successfully synthesized by heating a mixture of ferrocene and ammonium chloride at temperature as low as 200 °C and are treated with hydrochloric acid. Transmission and field emission scanning electron microscopy techniques are performed to examine the morphology and dimension of the samples. X-ray diffraction tests confirm the amorphous structure of the nanotubes. The Fourier transform infrared spectroscopy and Raman studies indicate that the treated α-CNTs consist of many defective walls and are more amorphous compared with the untreated α-CNTs. Ultraviolet–visible absorption studies reveal that the untreated and treated α-CNTs exhibit plasmon absorbance with high bandgaps of 4 eV and 4.35 eV, respectively.     

Quantitative characterization of nanoparticles in blood by transmission electron microscopy with a window-type microchip nanopipet

Transmission electron microscopy (TEM) is a unique and powerful tool for observation of nanoparticles. However, due to the uneven spatial distribution of particles conventionally dried on copper grids, TEM is rarely employed to evaluate the spatial distribution of nanoparticles in aqueous solutions. Here, we present a microchip nanopipet with a narrow chamber width for sorting nanoparticles from blood and preventing the aggregation of the particles during the drying process, enabling quantitative analysis of their aggregation/agglomeration states and the particle concentration in aqueous solutions. This microchip is adaptable to all commercial TEM holders. Such a nanopipet proves to be a simple and convenient sampling device for TEM image-based quantitative characterization.