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81.
Vijayalakshmi A Rajesh Kanna B Vijayalakshmi C 《Microscopy research and technique》2022,85(2):685-696
Malaria is a major public health concern, affecting over 3.2 billion people in 91 countries. The advent of digital microscopy and Machine learning with the aim of automating Plasmodium falciparum diagnosis extensively depends on the extracted image features. The color of the cells, plasma, and stained artifacts influence the topological, geometrical, and statistical parameters being used to extract image features. During microscopic image acquisition, custom adjustments to the condenser and color temperature controls often have an influence on the extracted statistical features. But, our human visual system sub-consciously adjusts the color and retains the originality in a different lighting environment. Despite the use of appropriate image preprocessing, findings from the literature indicate that statistical feature variations exist, allowing the risk of P. falciparum misinterpretation. In order to eliminate this pervasive variation, the current work focuses on preprocessing the extracted statistical features rather than the prepossessing of the source image. It begins with the augmentation of series images for a microscopic field by inducing illumination variations during the microscopic image acquisition stage. A set of such image series is analyzed using a Nonlinear Regression Model to generalize the relationship between microscopic images acquired with variable ambient brightness and a specific feature. The projection point of the centroid feature onto the brightness parameter is identified in the model and it is denoted as the optimum brightness factor (OBF). Using the model, the feature correction factor (CF) is calculated from the rate of change of feature values over the interval OBF, and the brightness of the test image is processed. The present work has investigated OBF for selected image textural features, namely Contrast, Homogeneity, Entropy, Energy, and Correlation individually from its co-occurrence matrices. For performance analysis, the best state-of-the-art method uses selected texture as a subset feature to evaluate the effectiveness of P. falciparum malaria classification. Then, the impact of proposed feature processing is evaluated on 274 blood smear images with and without Feature Correction (FC). As a result, the “p” value is less than .05, which leads to the result that it is highly significant and the classification accuracy and F-score of P. falciparum malaria are increased. 相似文献
82.
Shrikrishnan Sankaran Judith Becker Christoph Wittmann Arnzazu del Campo 《Small (Weinheim an der Bergstrasse, Germany)》2019,15(5)
On‐demand and long‐term delivery of drugs are common requirements in many therapeutic applications, not easy to be solved with available smart polymers for drug encapsulation. This work presents a fundamentally different concept to address such scenarios using a self‐replenishing and optogenetically controlled living material. It consists of a hydrogel containing an active endotoxin‐free Escherichia coli strain. The bacteria are metabolically and optogenetically engineered to secrete the antimicrobial and antitumoral drug deoxyviolacein in a light‐regulated manner. The permeable hydrogel matrix sustains a viable and functional bacterial population and permits diffusion and delivery of the synthesized drug to the surrounding medium at quantities regulated by light dose. Using a focused light beam, the site for synthesis and delivery of the drug can be freely defined. The living material is shown to maintain considerable levels of drug production and release for at least 42 days. These results prove the potential and flexibility that living materials containing engineered bacteria can offer for advanced therapeutic applications. 相似文献
83.
Grebel H Graziani JL Vijayalakshmi S Shacklette LW Stengel KM Eldada L Norwood R Yardley JT 《Applied optics》1997,36(36):9391-9395
To manipulate light propagation in optical waveguides, we have studied holographic, chirped structures within the waveguide's core. The holographic structures were embedded along the wave propagation direction and extended throughout the entire guide. Various self-imaging guides have been analyzed and realized to demonstrate the effect of different structures. 相似文献
84.
Radiochemistry - The liquid scintillation counting procedure for tritium quantification in environmental samples was optimized with respect to sample to cocktail volume ratio, fixing of region of... 相似文献
85.
Joseph Raj Alex Noel Junmin Chen Nersisson Ruban Mahesh Vijayalakshmi G. V. Zhuang Zhemin 《Pattern Analysis & Applications》2022,25(4):1001-1013
Pattern Analysis and Applications - In today's world, scene text detection is important for a wide range of scientific and industrial processes. Compared with text detection in documents, text... 相似文献
86.
Synthesis of dimethyl acetal of ketones: design of solid acid catalysts for one-pot acetalization reaction 总被引:1,自引:0,他引:1
Bejoy Thomas Sreedharan Prathapan Sankaran Sugunan 《Microporous and mesoporous materials》2005,80(1-3):65-72
The synthesis of dimethyl acetals of carbonyl compounds such as cyclohexanone, acetophenone, and benzophenone has successfully been carried out by the reaction between ketones and methanol using different solid acid catalysts. The strong influence of the textural properties of the catalysts such as acid amount and adsorption properties (surface area and pore volume) determine the catalytic activity. The molecular size of the reactants and products determine the acetalization ability of a particular ketone. The hydrophobicity of the various rare earth exchanged Mg–Y zeolites, K-10 montmorillonite clay, and cerium exchanged montmorillonite (which shows maximum activity) is more determinant than the number of active sites present on the catalyst. The optimum number of acidic sites as well as dehydrating ability of Ce3+-montmorillonite and K-10 montmorillonite clays and various rare earth exchanged Mg–Y zeolites seem to work well in shifting the equilibrium to the product side. 相似文献
87.
The effect of five different metal oxides on the pyrolysis of poly(ethylene oxide) (PEO), polyacrylamide (PAM), and poly(vinyl alcohol) (PVA) was investigated using thermogravimetry. The presence of metal oxide did not influence the degradation of PEO while the order of metal oxide on the degradation rate of PAM and PVA was PbO > Co3O4 > CuO > ZnO > Al2O3. The miscibility and the decomposition of PEO–PAM and PVA–PAM blends were also investigated. The blends were found to be immiscible and the presence of one polymer did not influence the degradation of the other polymer in the polymer blend. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 233–240, 2006 相似文献
88.
Novel Azo dyes possessing varying conjugation lengths and different extents of electron cloud delocalisation were synthesised and characterised and explored as sensitizers for dye-sensitised solar cells (DSSC). The envisaged azo dyes comprising of electron withdrawing and electron-donating moieties which are linked through conjugation bridges of varying lengths facilitated the prevalence of push–pull mechanism in the molecules. Optimisation of the geometry were performed for the synthesised compounds using B3LYP/ 6-31?+?G (d,p) level of density functional theory and their computed optical absorption and band gaps were validated with experimental results. The dyes exhibited molar extinction coefficients in the range of 3.2?×?104 to 4.2?×?104?mol?1?Lcm?1. The highest occupied molecular orbital (HOMO) was located between ?5.53 and ?5.03?eV for the various sensitizers synthesised and their lowest unoccupied molecular orbital (LUMO) was located between ?2.86 and ?3.08?eV. HOMO–LUMO gaps were in the range of 2.02–2.67?eV. Fill factor of the cells varied from 28% to 32% and the power conversion efficiencies ranged from 0.4% to 2.7%. This is the first time reporting of a systematic investigation, correlating the influence of nature and position of substituent, extending of conjugation and geometry of sensitizers on the photo physical properties of the sensitizers and the photovoltaic performance of corresponding DSSC.Highlights
The article focuses on push–pull azo dyes and were explored as promising candidate sensitizers for low cost dye-sensitised solar cells (DSSC).
The effect of chemical structure, extend of conjugation and geometry of the sensitizer on the photo physical properties of the sensitizers and the photovoltaic performance of DSSC were analysed.
89.
Jari Kolehmainen Ali Ozel Christopher M. Boyce Sankaran Sundaresan 《American Institute of Chemical Engineers》2017,63(6):1872-1891
To investigate the interplay between particle charging and hydrodynamics in fluidized beds, models for triboelectric charging and electrostatic forces were built into a computational fluid dynamics‐discrete element method model. Charge transfer was governed by the difference in effective work function between contacting materials as well as the electric field at the point of contact. Monodisperse particles were fluidized with an effective work function difference between the particles and the conducting walls. For smaller work function differences, hydrodynamics were not changed significantly as compared with an uncharged case. In these simulations, the average charge saturated at a value much lower than the value anticipated based on the work function difference, and a unimodal distribution of charges was observed. For larger work function differences, particles stuck to walls and bed height oscillations due to slugging were less pronounced. For these cases, a bimodal distribution of charges emerged due to effects from strong electric fields. © 2016 American Institute of Chemical Engineers AIChE J, 63: 1872–1891, 2017 相似文献
90.