Segmentation and range sensing using a moving-aperture lens

The use of a novel motorized lens to perform segmentation of image sequences is presented in this paper. The lens has the effect of introducing small, repeating movements of the camera center so that objects appear to translate in the image by an amount that depends on the distance from the plane of focus. For a stationary scene, optical flow magnitudes are therefore directly related to three-dimensional object distance from the observer. We describe a segmentation procedure that exploits these controlled observer movements and present experimental results that demonstrate the successful extraction of objects at different depths. Potential applications of our approach include image compositing, teleconferencing, and range estimation.Received: 4 July 2002, Accepted: 16 December 2002, Published online: 23 July 2003 Correspondence to: Amy E. Bell     

Amino‐functionalised mesoporous silica microspheres for immobilisation of Candida antarctica lipase B – application towards greener production of 2,5‐furandicarboxylic acid

In the present study, amino‐functionalised mesoporous silica microspheres were utilised as support for the covalent immobilisation of Candida antarctica lipase B (CaLB) for the subsequent production of 2,5‐furandicarboxylic acid (FDCA) from 2,5‐diformylfuran (DFF). Under the optimised operating conditions of pH 6.5, particle/enzyme ratio of 1.25:1.0 and glutaraldehyde concentration of 4 mM, a maximum CaLB immobilisation yield of 82.4% on silica microspheres was obtained in 12.25 h. The immobilised CaLB was used for the synthesis of alkyl esters, which were utilised along with hydrogen peroxide for FDCA synthesis. The biocatalytic conversion of 30 mM DFF dictated a 77–79% FDCA in 48 h at 30°C; where the turnover number and turnover frequency of immobilised CaLB were 6220.73 mol mol⁻¹ and 129.59 h⁻¹, respectively, for ethyl acetate, against 6297.65 mol mol⁻¹ and 131.2 h⁻¹, respectively, for ethyl butyrate. Upon examining the operational stability, the immobilised CaLB exhibited high stability till five cycles of FDCA production.Inspec keywords: mesoporous materials, organic compounds, biotechnology, silicon compounds, renewable materials, catalysis, catalysts, enzymes, thermal stability, biofuelOther keywords: FDCA production, amino‐functionalised mesoporous silica microspheres, greener production, 2,5‐furandicarboxylic acid, covalent immobilisation, 2,5‐diformylfuran, CaLB immobilisation, Candida antarctica lipase B immobilisation, ethyl butyrate, time 48.0 hour, temperature 30.0 degC, time 12.25 hour     

Modeling basal ganglia for understanding Parkinsonian reaching movements

We present a computational model that highlights the role of basal ganglia (BG) in generating simple reaching movements. The model is cast within the reinforcement learning (RL) framework with correspondence between RL components and neuroanatomy as follows: dopamine signal of substantia nigra pars compacta as the temporal difference error, striatum as the substrate for the critic, and the motor cortex as the actor. A key feature of this neurobiological interpretation is our hypothesis that the indirect pathway is the explorer. Chaotic activity, originating from the indirect pathway part of the model, drives the wandering, exploratory movements of the arm. Thus, the direct pathway subserves exploitation, while the indirect pathway subserves exploration. The motor cortex becomes more and more independent of the corrective influence of BG as training progresses. Reaching trajectories show diminishing variability with training. Reaching movements associated with Parkinson's disease (PD) are simulated by reducing dopamine and degrading the complexity of indirect pathway dynamics by switching it from chaotic to periodic behavior. Under the simulated PD conditions, the arm exhibits PD motor symptoms like tremor, bradykinesia and undershooting. The model echoes the notion that PD is a dynamical disease.     

Green synthesis of copper oxide nanoparticles and mosquito larvicidal activity against dengue,zika and chikungunya causing vector Aedes aegypti

In the present study, high purity copper oxide nanoparticles (NPs) were synthesised using Tridax procumbens leaf extract. Green syntheses of nano‐mosquitocides rely on plant compounds as reducing and stabilising agents. Copper oxide NPs were characterised using X‐ray diffraction (XRD) analysis, Fourier transform infrared (FT‐IR), Field‐emission scanning electron microscopy with energy dispersive spectroscopy, Ultraviolet–visible spectrophotometry and fluorescence spectroscopy. XRD studies of the NPs indicate crystalline nature which was perfectly matching with a monoclinic structure of bulk CuO with an average crystallite size of 16 nm. Formation of copper oxide NPs was confirmed by FT‐IR studies and photoluminescence spectra with emission peaks at 331, 411 and 433 nm were assigned to a near‐band‐edge emission band of CuO in the UV, violet and blue region. Gas chromatography–mass spectrometry studies inferred the phytochemical constituents of the leaf extract. Larvicidal activity of synthesised NPs using T. procumbens leaf extract was tested against Aedes aegypti species (dengue, chikungunya, zika and yellow fever transmit vector).Inspec keywords: photoluminescence, spectrophotometry, thermal analysis, chromatography, nanoparticles, antibacterial activity, field emission electron microscopy, microorganisms, wide band gap semiconductors, scanning electron microscopy, X‐ray diffraction, copper compounds, ultraviolet spectra, nanofabrication, X‐ray chemical analysis, crystallites, visible spectra, field emission scanning electron microscopy, nanobiotechnology, semiconductor materials, semiconductor growth, fluorescence, mass spectraOther keywords: energy dispersive spectroscopy, ultraviolet–visual spectrophotometry, fluorescence spectroscopy, chikungunya, green synthesis, mosquito larvicidal activity, zika, X‐ray diffraction analysis, field‐emission scanning electron microscopy, XRD, gas chromatography–mass spectrometry, copper oxide nanoparticles, dengue, tridax procumben leaf extract, nanomosquitocides, FTIR, monoclinic structure, crystallite size, photoluminescence spectra, near‐band‐edge emission band, phytochemical constituents, Aedes aegypti species, yellow fever transmit vector, CuO     

In Silico Study on Tumor-Size-Dependent Thermal Profiles inside an Anthropomorphic Female Breast Phantom Subjected to Multi-Dipole Antenna Array

Electromagnetic hyperthermia as a potent adjuvant for conventional cancer therapies can be considered valuable in modern oncology, as its task is to thermally destroy cancer cells exposed to high-frequency electromagnetic fields. Hyperthermia treatment planning based on computer in silico simulations has the potential to improve the localized heating of breast tissues through the use of the phased-array dipole applicators. Herein, we intended to improve our understanding of temperature estimation in an anatomically accurate female breast phantom embedded with a tumor, particularly when it is exposed to an eight-element dipole antenna matrix surrounding the breast tissues. The Maxwell equations coupled with the modified Pennes’ bioheat equation was solved in the modelled breast tissues using the finite-difference time-domain (FDTD) engine. The microwave (MW) applicators around the object were modelled with shortened half-wavelength dipole antennas operating at the same 1 GHz frequency, but with different input power and phases for the dipole sources. The total input power of an eight-dipole antenna matrix was set at 8 W so that the temperature in the breast tumor did not exceed 42 °C. Finding the optimal setting for each dipole antenna from the matrix was our primary objective. Such a procedure should form the basis of any successful hyperthermia treatment planning. We applied the algorithm of multi for multi-objective optimization for the power and phases for the dipole sources in terms of maximizing the specific absorption rate (SAR) parameter inside the breast tumor while minimizing this parameter in the healthy tissues. Electro-thermal simulations were performed for tumors of different radii to confirm the reliable operation of the given optimization procedure. In the next step, thermal profiles for tumors of various sizes were calculated for the optimal parameters of dipole sources. The computed results showed that larger tumors heated better than smaller tumors; however, the procedure worked well regardless of the tumor size. This verifies the effectiveness of the applied optimization method, regardless of the various stages of breast tumor development.     

Synthesis and characterization of Y (In,Mn) O3 blue pigment using the complex polymerization method (CPM)

In this paper, a new synthetic pathway is proposed for the system YIn_1-xMn_xO₃, a bright blue inorganic pigment, discovered in 2009. Blue pigment samples with increasing concentration of Mn³⁺ (x?=?0.08, 0.12 and 0.16) were prepared using the complex polymerization method (CPM) and compared with those synthesized via solid state reaction. All powders, the amorphous precursor from CPM and the starting materials for solid state method, were calcined at 1000, 1100, 1200 and 1300?°C for 12?h, and the resulting blue pigments were characterized by X-ray diffraction (XRD), colorimetric system CIE L*a*b* and Near infrared (NIR) reflectance measurements. XRD patterns and Rietveld Refinement show that the lowest temperature at which single hexagonal phase (isostructural to YInO₃) is formed is 1000?°C for CPM method and 1300?°C for conventional solid state method, respectively. The L*a*b* values demonstrate that the coloration of powders prepared by CPM exhibit temperature dependence below 1300?°C, a color shade shift from grayish blue to intense deep blue is observed when heating the samples from 1000 to 1300?°C. Blue pigments obtained by CPM have smaller particle size due to low temperatures and excellent near-infrared reflectance comparable to those by solid state method. Thus, providing advantages for application process and energy efficiency.     

Enhanced gravity particle classifier: Experiments with 3D printed device and computational fluid dynamics simulations

Centrifugal force developed in a fluid flow through closed spiral channel produces enhanced gravity environment to facilitate particle classification. The novel design is inspired by open channel spiral concentrators that are used in mineral processing industries. The concept is initially validated through computational fluid dynamics (CFD) simulations. Preferential movement of coarser particles, which experience greater centrifugal force, to the outer periphery was observed. These predictions are validated by conducting experiments on a 3D printed spiral classifier. The CFD simulations compared well with observed experimental separation function. The model was further used to conduct parametric study of various design and operational parameters. Simulations reveal that the cut-size could change from 8 μm to 260 μm depending on the splitter position. The novel device will allow a direct and online control of cut size/density when suitably enhanced with required mechanisms.     

Self-Assembly and Neurotoxicity of β-Amyloid (21–40) Peptide Fragment: The Regulatory Role of GxxxG Motifs

The three GxxxG repeating motifs from the C-terminal region of β-amyloid (Aβ) peptide play a significant role in regulating the aggregation kinetics of the peptide. Mutation of these glycine residues to leucine greatly accelerates the fibrillation process but generates a varied toxicity profile. Using an array of biophysical techniques, we demonstrated the uniqueness of the composite glycine residues in these structural repeats. We used solvent relaxation NMR spectroscopy to investigate the role played by the surrounding water molecules in determining the corresponding aggregation pathway. Notably, the conformational changes induced by Gly³³ and Gly³⁷ mutations result in significantly decreased toxicity in a neuronal cell line. Our results indicate that G³³xxxG³⁷ is the primary motif responsible for Aβ neurotoxicity, hence providing a direct structure–function correlation. Targeting this motif, therefore, can be a promising strategy to prevent neuronal cell death associated with Alzheimer's and other related diseases, such as type II diabetes and Parkinson's.     

Log-convexity of rate region in 802.11e WLANs

In this paper we establish the log-convexity of the rate region in 802.11 WLANs. This generalises previous results for Aloha networks and has immediate implications for optimisation based approaches to the analysis and design of 802.11 wireless networks.     

A Microprocessor-Based Full Voltage Starting of Induction Motor with Switched Capacitors

ABSTRACT

Increasing concerns over the starting of induction motors with high starting torque requirements have prompted engineers to seek methods of starting with full voltage and switched capacitors. This method provides ample acceleration torque with minimum voltage disturbances on the main bus. A highly reliable microprocessor-based starter with high performance has been developed. The hardware and software architecture of this starter and its starting aspects are described. The programmable automation provided here allows a flexibility in algorithms which can be altered or expanded easily. The performance goals designed also include protection of induction motor against overload, phase loss, wrong phase sequence and severe over voltage due to self-excitation.